The doctrine of the Trinity is a catholic teaching, a common possession of Christ’s whole church which expresses our understanding of the one who possesses and keeps us by his redeeming grace. Yet this doctrine that ought to foster a sense of unity among all orthodox believers has been a point of contention in recent times, not least in the world of evangelical theology where questions about the nature of the Son’s submission to the Father’s authority have generated significant controversy.1 My task in this essay is not to address any of these recent proposals directly but rather to consider how one of the church’s greatest theologians, Thomas Aquinas, handles the doctrine of the Trinity and how reflection on his work helps to cultivate the kind of theological discernment needed for faithful articulation of trinitarian teaching today. I propose to do this by focusing especially on the way in which Thomas sees God’s triune existence shaping God’s action in the economy of salvation. More specifically, we will focus on the question of how closely God’s own triune being corresponds to his activity in the incarnation. To show how Thomas’s perspective provides a helpful pathway into this matter, I will seek to do three things. First, I will set forth the basic concepts and structure of Thomas’s trinitarian doctrine, particularly his understanding of the divine processions, relations, persons and personal properties. Second, I will examine how this view of the processions and mutual relations of the persons gives shape to Thomas’s view of the mission and incarnation of the Son. Finally, I will comment on the strength of Thomas’s position on the correspondence between God’s trinitarian existence and his activity in the incarnation in dialogue with two alternative approaches to the question (those of Karl Barth and some Reformed orthodox theologians).

The Structure of Thomas’s Trinitarian Theology

In his Summa Theologiae, Thomas begins his account of the Trinity with a discussion of the triune processions (i.e., the Son’s eternal generation by the Father and the Spirit’s eternal procession from the Father and Son), for, according to Thomas, the divine persons are distinct from one another by “relations of origin.” He distinguishes a catholic view of the processions from the Arian and Sabellian views by stressing that procession in God is neither the procession of an effect from a cause (as Arius understood the Son’s procession) nor the procession of a cause to an effect (as Sabellius understood the Father to “proceed” in assuming flesh and to be called the Son in that respect). To preserve both the true deity and genuine distinction of the persons in orthodox trinitarianism, Thomas explains that procession here is to be understood not as an outward act but rather as an inward act that “remains in the agent himself.” It is an origination or “emanation” after the manner of a concept proceeding from the intellect or a spoken word proceeding from a speaker.2 The procession of the Son in particular is called “generation,” not because the Son passes from non-existence to existence or from potency to actuality as in the generation of something corruptible, but because he is one living who proceeds from a “living principle.” Such a procession is properly called “birth” (nativitas), and, indeed, the particular birth of the Son is of the sort in which the one born is properly called “begotten,” for he shares the same nature as the one who begets him (God the Father).3 Thomas believes the procession of the Son (who is aptly called the “Word”) occurs in the manner of an “intelligible action” where the concept of the thing known remains in the agent knowing (here, the Father), while the procession of the Spirit occurs in the manner of a “volitional action” where the object loved remains in the one willing and loving (in this case, two – both the Father and the Son).4 Yet Thomas is clear that the communication of the divine essence to the Son and Spirit in their processions does not multiply the divine essence or yield multiple deities. It is not that the divine essence is generated by the Father; rather, the Son is generated and, in being generated, receives from the Father the same essence the Father has.5

The processions in God require discussion of the relations of origin among the divine persons. The relation of the Father to the Son is called paternity; the relation of the Son to the Father is called filiation; the relation of the Father and Son to the Spirit is called spiration; the relation of the Spirit to the Father and Son is called procession.6 Thomas clarifies that these are not just logical relations existing in the human mind as it compares one thing to another. In that case, God would not really be Father, Son or Spirit, which would result in the error of Sabellianism. Instead, these relations are “real,” since the Father and Son, for example, are in fact “ordered toward one another” and have an “inclination” toward one another. This is supported by the fact that the processions in God occur within a single nature and order of being so that the relations among the persons are mutually constitutive.7 The relation of one person to another in the Trinity is, for Thomas, really identical with (the same “thing” as) the divine essence itself. If it were not the divine essence, it would be a creature. Accordingly, the relations among the divine persons are not accidents added to God’s essence; rather, their being (esse) is just that of the divine essence. Yet, this does not mean that the relation is the essence considered as such or absolutely, for what the relation is—in Thomas’s language, the proper ratio of the relation—is a reference or “habitude” toward another. Nor does it mean that the essence is reduced to a relation, for relation here does not signify all that the essence is.8 Thomas adds, against Sabellianism, that these relations are “really” distinct from one another—not as one “thing” (res) or being from another but as distinct in reality and not just in the human mind. For, if a real relation is present—a real “respect of one to another”—this assumes a real distinction between the one and the other. Thus, there is real distinction in God, not with respect to what is absolute (i.e., the essence) but with respect to what is relative (i.e., the persons). Indeed, though the relations are identical in their being to one and the same thing (i.e., the essence), they are not identical to one another since they are not identical to the essence absolutely but formally import or involve a respect toward another.9

The Concept of Person

After dealing with the concepts of procession and relation in the Summa Theologiae, Thomas is ready to discuss the concept of person.10 He affirms Boethius’s definition of “person” (an “individual substance of a rational nature,” which Thomas takes to be equivalent to the Greek hypostasis) and argues that it is rightly used to designate the Father, Son and Spirit, as long as it is recognized that certain creaturely factors that might be associated with the definition do not obtain in the doctrine of the Trinity. For example, individuation occurs by matter in many created substances, and created substances are often called such because they “stand under” accidents, but neither is true of God.11

Thomas then asks whether persona in the Trinity signifies relation, anticipating some of the careful work he will do a few questions later in the Summa Theologiae in clarifying the relationships among the various features (relation, person, essence and so on) included in the doctrine of the Trinity. Persona is not one of the “essential names” (like wisdom or power) that are attributed absolutely to God’s essence and are thus one in God. Yet, in itself, “person” does not have reference to another as paternity or filiation does. Thomas prefers to resolve the matter by saying that persona signifies relation “directly” and the divine essence “indirectly.” For, on the one hand, person signifies something that is distinct in a given nature rather than the nature as such (this particular individual as distinct from others), and, as noted, the persons of the Trinity are distinct by their relations toward one another. This means that persona must directly signify relation in the case of the Father, Son and Spirit. Yet, as noted, the relations of origin in the Trinity are not accidents added to God’s essence but really are the divine essence itself as it subsists in the distinct persons.12 Persona thus signifies not merely a relation but rather the relation as subsisting. In light of this, when Thomas calls the divine persons “relations,” he is not reducing the meaning of person to a mere respect or habitude toward another. He does affirm that persona signifies a distinct individual and that the divine persons are constituted as distinct from one another just by the relations of origin in God, which entails that the denotative content of persona as applied to the Father, Son and Spirit gives special prominence to the notion of relation. At the same time, the relations in the Trinity really are the divine essence as it subsists in the Father, Son and Spirit, so person as signifying a relation also includes all the fullness of God’s essence as it subsists in a certain manner. Persona thus does not signify relation as such but only as the constitutive, individuating principle of the hypostasis.13 Accordingly, given that hypostasis in God is really identical with God’s essence, persona may from another angle be said to signify the essence directly and relation indirectly as an individuating factor. Given his emphasis on persona being a name suited—not merely by amended usage but “by the fittingness of its own signification”—to the Father, Son and Spirit in their distinctness from one another, Thomas’s view of the term differs from that of Augustine, who did not view persona as especially suited to designate the Father, Son and Spirit. For Augustine, persona designates the three simply because something has to be said when someone asks “three what?” in discussion of the Trinity.14 However, with Augustine, Thomas can say that because persona is equivalent to hypostasis and because in God hypostasis (‘what is’) and essence (that ‘by which’ a hypostasis is) are really identical, the content of the term persona includes the divine essence.15 

The Concept of “Notion”

Another important feature of Thomas’s doctrine of the Trinity is the concept of a “notion.” By “notion” Thomas means an abstract representation of the distinct character of a divine person, by which the person can be readily identified by us. He draws attention to five notions that set forth the distinct subsistences of the Father, Son and Spirit. To the Father belong “innascibility” (not proceeding from another person) and paternity (his begetting of the Son); to the Son belongs filiation (proceeding from the Father in a filial manner); to both the Father and Son belongs common spiration (eternally bringing forth the Holy Spirit); to the Spirit belongs procession (coming forth from the Father and Son in what Thomas regards as a volitional manner). Four of these are relations (innascibility expresses no relation of the Father to another person and so is the exception). Four of these are unique to one person (common spiriation belongs to two persons and so is the exception here), and these four are thus called properties (characteristics proper to just one person). Three of these are what Thomas calls “personal” in the sense that they are fundamentally constitutive of the persons: paternity, filiation, procession.16 Significantly, Thomas does not describe the notions or personal properties after the manner of creaturely properties, which are, in classical metaphysics, accidents (things that inhere in another in order to exist) naturally and automatically adjoined to the essence of a thing (as risibility is to human nature). Instead, to uphold God’s simplicity and confirm that there are no accidents in the divine persons, he explains that the personal properties are really identical to the divine persons themselves. They simply prescind the peculiar relative manner of subsisting of each person and express it in the abstract as a formal ratio by which each person is distinct from the others. The function of the personal properties is therefore, by an alternative mode of signifying the persons, to provide an answer to the question of how (quo, “by what”) there are three persons in God.17

To connect this at a very general level to contemporary debates about the distinctions among the divine persons, it is worth noting that Thomas does not envision any faculties (intellect, will) or inhering features that might distinguish the persons, only their relations to one another. Anything included in the divine essence itself (e.g., intellect and will) is ruled out as an individuating factor that might distinguish the divine persons. The principles of individuation in the doctrine of the Trinity are strictly the persons’ relative modes of subsisting: begetting the Son (the Father’s mode of subsisting), proceeding filially from the Father (the Son’s mode of subsisting) and proceeding from the Father and Son (the Spirit’s mode of subsisting). Even the power by which the Father generates the Son, for example, is not a power unique to the Father but simply the common divine power as modified and eternally enacted by the Father under a relation to the Son.18

With this basic understanding of the structure of Thomas’s trinitarian theology in hand, it is now fitting to inquire about how he views the relationship between God’s own triune being and his activity in the economy. How do the processions, relations of origin and notions or personal properties give shape to God’s outward works, particularly the mission and incarnation of the Son? Do all the dynamics of the Son’s mission and incarnation (especially his submission to the Father) have an antecedent in the Son’s procession and eternal relation to the Father? These questions will occupy us in the next section.

The Mission, Incarnation and Submission of the Son

It is relevant to our discussion of God’s activity in the incarnation that when Thomas discusses the individual persons in greater detail in the Summa Theologiae, he touches upon the equality of the Father and Son. He explores the question of whether the Father is rightly called a “principle” of the Son and argues that he is rightly called such because a principle is simply “that by which something proceeds.” “Principle” has a wider meaning than “cause,” which, though it is used by the Greek fathers in the doctrine of the Trinity, is imprudent to use in this case since causal language suggests a “diversity of substance.” While Thomas, quoting Hilary of Poitiers, is willing to grant a certain auctoritas (a word that may denote “authority” or “originating power”) to the Father in that the Father begets the Son, he refuses to allow any “subjection” (subjectio) or “minority” or “less-ness” (minoritas) pertaining “in any way” to the Son (or the Spirit). For, as he puts it, “every occasion of error should be avoided.”19

This links up with Thomas’s later discussion of whether the Son is equal to the Father in greatness (secundum magnitudinem). Philippians 2:6 is crucial here: the Son did not consider it “robbery” (rapina in the Latin text Thomas uses) to be equal to God the Father.20 For the Son receives from the Father the very nature of the Father, and greatness is nothing but the “perfection of the nature itself.” That the Son is indeed equal to the Father is further underscored by the fact that his generation is not like the transition from potentiality to actuality that occurs in human generation; the Son is generated eternally by the Father, with no gradual development or perfection taking place over time. Thus, when Christ states that “the Father is greater than I” (John 14:28), this pertains to his human nature. So too 1 Corinthians 15:28 (“the Son himself will be subject to him who subjects all things to him”): “those words are understood as said about Christ according to the human nature, in which he is less than the Father and subject to him.” Thomas references Athanasius here, affirming that the Son is “equal to the Father according to divinity, less than the Father according to humanity.” He then references Hilary again, apparently conceding that the Father might be called “greater” just in the sense that he generates the Son and in so doing communicates the divine nature to him. However, the quotation of Hilary continues and affirms that “he is not less to whom the one being is given.”21 Thomas then includes another quote from Hilary where Hilary distinguishes between the subjection of God the Son and the subjection of creatures: “the subjection of the Son is a natural devotion (naturae pietas),” which is, according to Thomas, “recognition of the auctoritas of the Father,” “but the subjection of the rest is a matter of the weakness of creation.”22

That Thomas would not posit a subordination or obedience of the Son as God or in his eternal relation to the Father is clear not only from the strong statements already mentioned here but also from his Christology. In the third part of the Summa Theologiae, Thomas directly addresses the question of whether the Son is “subject” to the Father, and there the subjection and obedience of the Son are restricted to his human nature alone (or, better, to the Son only as he subsists and acts in his human nature). It is proper to humanity to be subject to God’s authority (potestas) and to be required to obey God’s commands. It is therefore according to his human nature that Jesus always does what is pleasing to the Father (John 8:29) and that he obeys the Father even unto death (Phil 2:8). In this article, Thomas takes into account an objection that might be raised on the basis of the fact that only creatures are subject to God. In response, Thomas does not argue that a divine person as such might be subject to another divine person. Rather, he accepts that only creatures are subject to God and then argues that while Christ is not a creature “simply” (without any added qualification), he is a creature according to his human nature and may therefore be subject to the Father according to his human nature. Indeed, Thomas writes, while it is permissible to say that Christ is subject to the Father and leave the qualification “according to his human nature” to be implicit, it is wiser to add the qualification in order to avoid the error of Arius, who held that the Son is less (minor) than the Father.23

The restriction of submission and obedience to Christ in his human nature appears in Thomas’s commentary on the Gospel of John. For example, in John 5:19-20 Jesus clarifies that he is not in competition with the Father by saying that he does nothing “from himself” but only what he sees the Father doing. Whatever the Father does, the Son also does, for the Father loves the Son and shows him what he is doing. Thomas takes it that these are works performed by the Son according to his divine nature and thus rules out that this passage might imply a minority of the Son in relation to the Father, for such a minority would be applicable to Christ only according to his human nature. Drawing upon Augustine, then, Thomas argues that the Son never acting “from himself” refers back to his eternal relation to the Father. Just as the Son’s very being (esse) is “from the Father,” so too does he share in the one divine power and action “from the Father.”24 Thomas paraphrases: “the Son, as he does not have esse except from the Father, so he is not able to do anything except from the Father.” Likewise, that the Father “shows” the Son what he does indicates not that the Father acts and then the Son subsequently learns and imitates but rather that the Father has communicated the divine knowledge to the Son as he has communicated the one divine essence and power to the Son in his eternal generation.25

To be sure, Christ also uses the future tense and says that the Father will show him greater works (5:20b), but Thomas holds that this signals not that the Father is waiting to give the divine knowledge, power and authority to the Son in the future but instead that the Father will “show” the aforementioned works to the Son (and to all who will marvel at them) in that he will execute these works through the Son at a time in the future and make them known to the world at that point. These greater works are epitomized in the resurrection of the dead, which the Father and Son accomplish together (5:21). The fact that Jesus says the Son gives life “to whom he wills” evokes Thomas’s comment that the Father and Son do not give life to different sets of persons. Rather, the Father and Son share the one divine will and the Father always works through the Son (though not as if the Son were a mere “instrument”). Jesus then says that the Father judges no one but gives all judgment to the Son (5:22). Thomas then notes two traditional expositions of this verse. Augustine’s exposition suggests that Jesus is no longer talking about himself acting according to his divine nature (in which he always acts with and “from” the Father). If the Son alone is acting in the judgment, it must be according to his human nature (compare Acts 10:42), which would be fitting since this means that those who receive damnation at the judgment will not see God in his divine nature and will not unjustly receive the beatific vision. The “more literal” exposition of Hilary and John Chrysostom differs slightly in positing simply that the Son has “judgment” from the Father in that he has the divine wisdom (as opposed to “judgment” in the sense of granting approval and condemnation to others) from the Father by which he performs his works.26

Later in John 5 Jesus says again that he does nothing “from himself” but judges as he “hears” and that his judgment is just because he seeks not his own will but the will of the one who sent him (v. 30). Here Thomas comments that this can be taken with reference to the Son as man, in which case “hearing” would have the sense of “obeying.” In that case obedience could be intended because, if the text speaks of Christ in his human nature, it speaks of him in that respect in which he is “less” than the Father and could therefore receive a command from him. Christ’s human will, Thomas points out, is always “ruled” by the divine will. Alternatively, Jesus could be speaking of himself with regard to his being the divine Son, in which case the language of “hearing” is employed just because we receive knowledge often by hearing and Christ receives the divine knowledge from the Father in his eternal generation. If it is Jesus in his divine nature and action in view, then the text does not imply that the Father and Son have two distinct divine wills but rather reflects the fact that the Son has the divine will “from” the Father and therefore fulfills it as he has it “from another.” Thomas paraphrases Christ’s words: “I do not seek my own will, which is originally mine from myself, but [a will] which is mine from another, namely, the Father.”27

The key observations are (1) that Thomas believes that filial obedience applies to Christ only where the biblical text speaks of Christ in his human nature, for he is less than the Father and commanded by the Father according to that human nature alone, and (2) that he believes that Christ in his divine nature always wills and acts from the Father in keeping with his eternal procession from and relation to the Father. There is therefore in Thomas’s theology a significant dissimilarity between the dynamic of submission and obedience in the economy and the eternal relation of the Son to the Father. This is because in the incarnation Christ has a human nature and will as well as the divine nature and will and therefore can and does act in a manner (i.e., submissively) that does not apply to him in his divine nature and eternal relation to the Father. Yet, there is still an important correspondence between Christ’s divine action in the economy and his eternal relationship to the Father, namely, that he acts from the Father just as he eternally has the divine essence and power from the Father. In other words, his mode of acting corresponds to and derives from his eternal mode of subsisting in the Godhead.28

But, one might ask, what about the Son being sent of the Father? Does that imply that, even prior to his assumption of a human nature, the Son submits to the Father? Thomas’s description of the sending or “mission” of the Son does not involve subordination or obedience. In fact, the first objection in the Summa Theologiae raised against one divine person sending another insists that sending and being sent would entail superiority and inferiority. Thomas responds not by granting that the Son might be less than the Father but by stating that sending implies superiority and inferiority only if it occurs by the command of one who is greater or by the counsel of one who is wiser. In God, however, since the Son is equal to the Father, the mission of the Son is simply his coming forth “from” the Father “according to origin” (not according to “command” or “counsel”) and coming forth “toward” his human nature. The mission thus consists of (1) a relation to the one from whom he is sent (the Father) and (2) a relation to that toward which he is sent to exist in a new mode, the terminus ad quem here being his human nature. Put differently, the mission is the act of the eternal procession with the addition of a temporal term and effect.29

Given the relationship between the Son’s mission and his eternal, constitutive procession and relation to the Father, there is a dissimilarity between the (human) obedience of the Son after his assumption of a human nature and his coming forth from the Father to assume that nature. However, according to Thomas, there is still an important connection between the Son’s mission and his procession because a divine person may be “sent” only insofar as he proceeds from another. As noted, procession from another is included in the very definition of mission. By contrast, it does not “agree” with the Father to be sent because he does not proceed from another in the Trinity.30 At one point in his account of the incarnation, though, Thomas is arguably less concerned to maintain this correspondence between the structure of the economy and the eternal order of the divine persons. He asks whether any of the three persons (not just the Son) could have assumed a human nature, and he answers affirmatively. For the divine power is “commonly” and “indifferently” present in the three persons. If the Son, then, had the power to be incarnate, so too did the Father (and Spirit). In addition, though Christ is the “Son of Man,” this is only a “temporal sonship” that (unlike eternal sonship) does not constitute the person of the Son and therefore could have been applied to the Father or Spirit without undoing the eternal order of the persons. In other words, the “temporal birth” in the incarnation would not undermine the innascibility of the Father. Indeed, the reason why the Son is said to be “sent” in the incarnation—and being sent does conflict with innascibility—is that he takes on flesh as a divine person who proceeds from another, not that taking on flesh itself entails being sent or proceeding from another.31

So far we have seen that Thomas recognizes a significant dissimilarity between the filial submission of the Son according to his human nature in the incarnation and the Son’s eternal relation to the Father. This is because, in Thomas’s view, submission involves receiving a command from another, which itself involves being in some way “less” than the one who commands. Moreover, his commitment to the traditional principle that the outward works of the Trinity are undivided (opera Trinitatis ad extra indivisa sunt) implicitly precludes any divine submission on the part of the Son. For, as Thomas emphasizes, the Father and Son (with the Spirit) do not possess distinct divine wills or perform distinct divine actions but rather will and perform the same actions, each according to his peculiar manner of having the divine essence and power. The dissimilarity here holds true even with respect to the Son being sent of the Father and coming forth from the Father to assume a human nature. Indeed, as noted, Thomas is willing to say that the Father (or Spirit) could have assumed human flesh in the incarnation. To appreciate and assess Thomas’s position a little better, it may help to consider it alongside two other approaches to the correspondence between God’s own triune being and his triune action in the incarnation.

Two Alternative Approaches

Karl Barth
Here we will touch briefly upon how Karl Barth and some of the Reformed orthodox handle the questions at hand. Barth insists on a strong correspondence between God in himself and God for us in the economy of salvation, and he is particularly forceful on this point when he deals with the obedience of the Son.32 For Barth, there is no discrepancy between God in himself and God for us in the incarnation because God in himself is already characterized by humility: “for God it is just as natural to be lowly as it is to be high.”33 Or,

What marks out God above all false gods is that they are not capable and ready for [condescension to us]. In their otherworldliness and supernaturalness and otherness, etc., the gods are a reflection of the human pride which will not unbend, which will not stoop to that which is beneath it. God is not proud. In His high majesty He is humble. It is in this high humility that He speaks and acts as the God who reconciles the world to Himself.34

Barth sees this humility in the incarnate Son’s obedience to the Father and ultimately locates that obedience back in the Son’s very deity and eternal relation to the Father.  The meaning of “deity,” Barth writes,

cannot be gathered from any notion of a supreme, absolute, non-worldly being.It can be learned only from what took place in Christ….Who the one true God is, and what He is, i.e., what is His being as God, and therefore His deity, His “divine nature,” which is also the divine nature of Jesus Christ if He is very God – all this we have to discover from the fact that as such He is very man and a partaker of human nature, from His becoming man, from His incarnation and from what He has done and suffered in the flesh.35

But this revelation of deity in the incarnation takes place in the Son’s “self-humiliation” and obedience to the Father. Yet even in the midst of this humiliation and obedience, it must be affirmed that the Son does not alter or relinquish his deity, lest his atoning and reconciling work be emptied of its efficacy. “He went into a strange land, but even there, and especially there, He never became a stranger to Himself.”36

Therefore, to ensure that the genuine condescension of the Son aligns with his deity in its original fullness, Barth infers that such condescension is not a departure from true deity but rather always was eternally included in “the most inward depth of His Godhead.” Since “God is in Christ” and “what the man Jesus does is God’s own work,” the “self-humbling of Jesus Christ as an act of obedience cannot be alien to God.” Barth concedes that “it is a difficult and even an elusive thing to speak of obedience which takes place in God himself,” but he believes it is possible to speak of such obedience without undermining the homoousia of the Son like historical forms of “subordinationism” have done. He is committed to the notion that superiority and subordination cannot be purely economic phenomena but must apply to God’s “proper being,” for otherwise the Son’s obedience would not “bring us into touch with God himself.”37 Still this must not be taken to imply inequality among the divine persons, for upholding the full deity of the Son in order to secure the efficacy of his work is precisely the point here. Barth’s strategy in addressing this problem is to emphasize that if there is a “prius and posterius, a superiority and subordination” in God, it need not include the human dynamic of “degradation” and “inferiority.” Instead of assuming that subordination entails a lack or deprivation on the part of God the Son, we should let our conception of subordination be corrected by the particular triune being of God, in which there is subordination with dignity rather than inferiority.38 In Barth’s position, then, “we cannot avoid the astounding conclusion of a divine obedience.” As the Son obeys the Father in the incarnation, “He does not do it without any correspondence to, but as the strangely logical final continuation of, the history in which he is God.”39

Reformed Orthodoxy
Though they are not without diverse opinions on various theological topics, earlier Reformed theologians of the sixteenth and seventeenth centuries treat the obedience of the Son differently than Barth does, affirming the more traditional position advocated by Thomas and yet also differing from him in some relatively minor but still noteworthy ways. Unlike Barth and with Thomas, they do not posit a subordination of the Son in his deity or his constitutive, eternal relation to the Father. The “minority” and subordination of the Son pertain to him with respect to his human nature.40 Yet, according to many of the Reformed orthodox, subordination and obedience pertain to him with respect to his economic, mediatorial office as well. In other words, the Son’s subjection to the Father, though not applicable to the Son as God, does apply to him in his voluntary condescension in his economic role.41

The development of the concept of the pactum salutis (“covenant of redemption”) in Reformed thought during this period provided fresh angles from which to consider the Son’s submission to the Father.42 The concept of the pactum salutis distills the fact that in Scripture the Father promises to give to the Son a chosen people for whose salvation the Son should be the sponsor and mediator, while the Son promises to fulfill his covenantal obligations in perfect obedience to the Father’s will (see, e.g., Isa 42:6; Jn 6:37-40; 17:6-12; Heb 7:21-28; 10:5-10). The Reformed were aware that this distillation of biblical teaching might be taken to imply an eternal submission of the Son to the Father but are careful to reject that inference.

Johannes Coccejus, for example, writes that, in the covenant between the Father and the Son, the Father “stipulates” obedience for the Son and thus calls the Son “my servant” (e.g., Isa. 42:1). The covenant accordingly “imports an emptying (exinanitio) of the Son toward assuming the form of man.” Throughout his incarnate life, the Son is a “voluntary servant” of the Father, submitting himself to the Father’s will (Ps 40:6-7; Jn 6:38-40; Rom 5:18-19; Heb 10:5-10). In this “economy,” the Father has the role of “legislator” and “ruler,” exercising both justice and mercy through the mediatorial work of the Son, and is often called “God” in a special way since he “performs this right of deity.” But this does not mean that the Son submits to the Father in the founding itself of the pactum salutis (or in his constitutive personal relation to the Father). Unlike Adam when he entered a covenant with God, the Son “was held by no law” in entering this covenant, for he did not think it “robbery” to be equal with God (the Father) (Phil 2:6). The Son was not “less” than the Father “outside the state of humiliation (status exinanitionis) and according to deity.” Indeed, it was a matter of the free grace of the Son no less than the Father that the Son took up his role as the “sponsor” of God’s people. Hence it is after assuming flesh and being born of a woman that the Son lives “under the law” (so Gal 4:4).43

Coccejus’s fellow Dutch orthodox theologian Herman Witsius handles these issues similarly. He reasons that the acts of generation and spiration imply no “distinction of dignity” among the persons, for in those acts one and the same divine essence is communicated to the Son and Spirit. Those acts convey no “authority,” “right” or “rule” of the Father toward the Son or Spirit. Nor does the mission of a divine person convey any of this, for mission is “wholly economical” (tota kat’ oikonomian) and “founded in the common counsel of the whole Trinity.” The Father is peculiarly called “God” and called “greater” than the Son not with respect to God’s own triune being (kata theologian) but with respect to the Son’s humanity and with respect to the “economy of humiliation” (kat’ oikonomian, oeconomia exinanitionis) and the covenant in which the Son is mediator.44

In treating the pactum salutis, Witsius invokes a threefold distinction regarding how the mediator can be considered: (1) as God; (2) as man; (3) as mediator or “God-man” (theanthrōpos). As man and born of a woman, the Son “subjects himself to the law” (Gal. 4:4). But as God “he is subject to no law, to no superior person, and is not able to be subjected.” For this is “repugnant” to that deity which the Son shares with the Father.  No subjection pertains to deity but only the “highest eminence.” Here Witsius quotes approvingly the pointed words of an ancient imperial decree: “the Christian is one who believes that the deity of the Father, Son and Holy Spirit is one in equal power (or “authority,” exousia), that the deity is one under equal majesty; truly he who teaches against the things now said is a heretic.” In light of this, Witsius clarifies that the Son taking up the role of “sponsor” of the people of God “imports no subjection,” for the Son accepts this role by an act of his divine will and chooses to subject himself to the Father not as God but as man. He is bound by no necessity to do this, acting with the Father (and Spirit) according to his free good pleasure.45 Yet, though Witsius refuses to say that Christ is subject to any law with respect to his divine nature and in the founding of the pactum salutis, he grants that after the assumption of the human nature and because of the union of Christ’s two natures his divine nature is “drawn into the company of this subjection.”46 The divine nature itself as “characterized” in the Son does not undergo subjection, but in union with the Son’s human nature it does not show “all its magnificence” or hinder the Son as man in his service to the Father. This not a “real negation of divine superiority” but only an “economic concealment” (oeconomica occultatio). In keeping with the Reformed emphasis on the “real” (not merely “verbal”) communication of the properties and experiences of the human nature to the person of the Son, Witsius, without promoting any divine subordination of the Son to the Father, writes that there is a “relation of inferiority” and an economic obedience that genuinely apply not just to the human nature but to the person of the God-man himself. Were the arrangement not so, one would have either a divine Son who could not perform the work of obedience or a merely human person whose obedience would not suffice to merit our salvation.47

Another difference between Thomas and many of the Reformed authors is that the latter hold that only the Son could have been incarnate. In his large work on Christology, Jerome Zanchi, for example, though a debtor to Thomas in his theologizing, draws upon Augustine and other writers and argues that the Father could not have been incarnate. He invokes Peter Lombard to make the point that the incarnation is the “mission itself of the Son, by which he is said to have been sent from the Father.” This view of the relationship between incarnation and mission of course precludes the (innascible) Father being incarnate.48 Turretin likewise envisions a stronger connection between incarnation and mission: “the Father is not able to be incarnate, for as he is first in order, he is not able to be sent by anyone, or to act as mediator toward the Son and Holy Spirit.” Turretin insists that the logic of the processions and the attendant proper modes of acting of the persons shape the logic of the incarnation. It is the beloved Son and perfect image of the Father who is suited to make us God’s beloved in whom he delights and to restore the image of God in us. It is the one through whom all things were made who is fit to be the one through whom they are remade.49

Comparison with Thomas Aquinas
Though this has been a primarily historical and descriptive essay to this point, what might be said about the strength of Thomas’s position, particularly now that it can be viewed alongside other notable approaches to the relationship between God’s triune being and his activity in the incarnation? First, while there is not space to discuss the issues at great length on the constructive level, in my judgment Thomas’s reasoning is not only sound but also vital to an orthodox view of the Trinity where he reasons that the equality and, indeed, numerical unity of the divine essence, wisdom, will, power and action of the divine persons precludes a divine submission of the Son to the Father. This is hardly an invention of Thomas but is rather drawn from the well of catholic patristic theology and, more importantly, is a setting forth of the scriptural teaching that there is but one God and that the Son is fully God. If the Son shares the one divine will and action with the Father (and Spirit)—even as he performs that action in a mode expressive of his personal mode of subsisting—in what way would it be meaningful to speak of the Son as God acquiescing to a prior determination of the Father?50 I would emphasize, then, that when Thomas identifies a dissimilarity between the filial obedience that takes place in the economy and the eternal personal relation of the Son to the Father, it is important that we follow him (and others) in making this move.

Second, at the same time, Barth’s emphasis on the alignment of God’s being and economic action is, in my view, worth taking into account here. His guiding question in the material outlined above in Church Dogmatics IV.1—Quo jure Deus homo, “by what right does God become man?”51—regarding what it is in God’s being that entails his fitness for the incarnation pushes us to think carefully about the correspondence between who God is and what God does. However, to my mind, positing a divine obedience of the Son and locating this in his eternal relation to the Father is not necessary to uphold that the divine Son himself obeys and atones for sin or even that the Son’s economic relationship to the Father expresses something of his eternal filial relation toward the Father.52 In fact, positing such divine obedience on the part of the Son seems much less compelling when we note that in Scripture it is the human obedience of the divine Son that is so essential to undoing the first Adam’s work (cf. Rom 5:18-19; Gal 4:4; Heb 2:9-18).

Third, a catholic and Thomistic understanding of the Son’s submission to the Father may be enriched by the early Reformed discussion of the pactum salutis and the Son’s mediatorial role. Taking into account the pactum salutis can help us to reinforce (1) that the Son was not “less” than the Father or under his command in eternally willing to assume his economic role and (2) that, even if the concept of mission did include some authority structure, mission is already located under the economy established by the free decree of the whole Trinity. Further, appropriating the notion that the Son submits to the Father not only in his human nature but also in his mediatorial office broadens our options for interpreting biblical statements about the Son: they may apply to him with respect to his divine essence, his eternal procession from the Father, his proper mode of acting from the Father, his human nature or his mediatorial office.

Finally, Thomas’s assertion that the Father (or Spirit) might have been incarnate may understate the connection between the logic of the processions and the logic of the economy, especially if the incarnation does involve a divine person being sent (not just the enfleshment of a divine person who may or may not be sent). For if the incarnation entails being sent and if being sent presupposes procession or origin from another divine person, then only one who proceeds from another can be incarnate. At this point Thomas’s argument that any divine person could be incarnate because they share the same divine power would lose its force. For it would not be the common divine power taken absolutely that enables a divine person to be incarnate but rather that power as it is distinctly modified by the Son who is generated by the Father. Because this common power is in the Son alone in this particular manner, he alone is able to incarnate. In my estimation the incarnation does presuppose a coming forth from another, and I see Thomas’s denial of this as a weakness in his (on the whole, very compelling) approach to the relationship between God’s triune being and his activity in the incarnation.

In this essay I have attempted to shed light on the central concepts and structure of Thomas Aquinas’s trinitarian thought, with a view to examining how Thomas sees God’s triune being giving shape to his economic action in the incarnation. We explored the meaning and function of the concepts of procession, relation, person and notion or personal property in the doctrine of the Trinity. From here, we looked at how this framework promotes for Thomas a strong sense of the equality of the divine persons. When pressed to deal with biblical statements about the Son being “less” than the Father and obeying the Father, Thomas resolutely argues that the minority and submission of the Son pertain to him according to his human nature, which entails a dissimilarity between the filial obedience of the Son in the economy and his eternal, constitutive relation to the Father. However, in biblical texts such as John 5:19-30, Thomas also identifies one way in which the economy is shaped by and corresponds to the processions in God: the Son wills and acts from the Father in the economy just as he proceeds from the Father eternally. Indeed, the Son can be sent from the Father to assume a human nature only by virtue of his eternal procession from the Father. Yet, according to Thomas, the incarnation does not necessarily presuppose a sending of one divine person from another, so even the Father could have been incarnate.

We then considered two alternative approaches to the correspondence between God’s triune being and his activity in the incarnation (those of Karl Barth and some of the Reformed scholastics). After noting similarities and differences among the approaches, I indicated that in my estimation Thomas (and the Reformed orthodox) are right to avoid positing any divine obedience of the Son and to attribute the economic obedience to the Son in his human nature, with the Reformed usefully underscoring that the obedience pertains to the person of the God-man himself in his mediatorial office. While Barth does helpfully encourage us to think about what it is in God’s being that renders him fit for the incarnation and secures the genuine presence of God himself in his incarnate work, in my view this need not compel us to posit a divine obedience of the Son, particularly if we hold that the incarnation presupposes the mission of the Son and flows out of the personal character of God the Son as the Father’s perfect filial image and the one through whom the Father always acts. Through this study, then, I hope to have shown that a catholic trinitarianism in which there is no divine obedience of the Son can cohere with a significant alignment of God’s action in the incarnation and God’s own triune being.

1 For relevant literature, see, e.g., Wayne Grudem, Systematic Theology: An Introduction to Biblical Doctrine (Grand Rapids: Zondervan, 1994), 249-52; Bruce A. Ware, Father, Son, and Holy Spirit: Relationships, Roles, and Relevance (Wheaton: Crossway, 2005);Kevin Giles, Jesus and the Father: Modern Evangelicals Reinvent the Trinity (Grand Rapids: Zondervan, 2006); Millard J. Erickson, Who’s Tampering with the Trinity: An Assessment of the Subordination Debate (Grand Rapids: Kregel, 2009); Dennis W. Jowers and H. Wayne House, eds., The New Evangelical Subordinationism?  Perspectives on the Equality of God the Father and God the Son (Eugene: Wipf and Stock, 2012); Bruce A. Ware and John Starke, eds., One God in Three Persons: Unity of Essence, Distinction of Persons, Implications for Life (Wheaton: Crossway, 2015); Michael J. Ovey, Your Will Be Done: Exploring Eternal Subordination, Divine Monarchy and Divine Humility (London: Latimer Trust, 2016).

2 Thomas Aquinas, Summa Theologiae, Pars Prima, in Opera Omnia (vol. 4; Leonine ed.; Rome: ex Typographia Polyglotta, 1888), Ia.27.1, 305-6 (hereafter ST).  ET: Summa Theologica (5 vols.; trans. Fathers of the English Dominican Province; New York: Benziger Bros., 1948).

3 Thomas, ST, Ia.27.2 corp., 309.

4 Thomas, ST, Ia.27.3 corp., 311.

5 So Contra Errores Graecorum, in Opera Omnia (vol. 40A; Leonine ed.; Rome: ad Sanctae Sabinae, 1967), I.4-5, 74-5.

6 Thomas, ST, Ia.28.4, 325-6.  Thomas believes the processions or origins and the relations signify the same “thing” (re non differant) but do so with different modes of signification.  “Generation,” for example, signifies the Father’s relative act of begetting the Son as an action (per modum actus)while “paternity” signifies the Father’s relative act of begetting the Son as a formal expression of that relation that is constitutive of the Father (per modum formae).  Both origin and relation are principles of distinction among the divine persons, but in our understanding, because a relation or property like “paternity” expresses something intrinsic to the Father, it logically precedes “generation,” a term indicating action directed toward another (Ia.40.2 corp. and ad 4, 413, 414; cf. 40.4, 418; 41.1 ad 2, 421-2; cf. De Potentia,in Quaestiones Disputatae (vol. 2; 10th ed.; ed. P. Bazzi et al.; Turin and Rome: Marietti, 1965), II.5 ad 8, 36).

7 Thomas, ST, Ia.28.1 corp. and ad 3, 318, 319.

8 Thomas, ST, Ia.28.2 corp. and ad 3, 321, 322.  That the essence is not made relative to a divine person is further secured by the fact that a person’s relation here is not ordered to the essence but rather to another person with whom that person stands in relation.

9 Thomas, ST, Ia.28.3 corp. and ad 1, 324.  Cf. Ia.39.1 ad 1, 396-7.  Thomas also clarifies that while the “absolute” divine properties like wisdom and goodness may be one and the same thing (the divine essence), the relations of the persons are “mutually opposed” and therefore cannot be just one subsistent.  Hence the presence of multiple mutually opposed relations entails multiple subsisting persons (Ia.30.1 ad 2, 336).

10 Gilles Emery observes that Thomas is following a logical sequence here that is designed to integrate procession, relation and essence (discussed before the Trinity in the Summa Theologiae) in the concept of person (“Essentialism or Personalism in the Treatise on God in Saint Thomas Aquinas?,” The Thomist 64 (2000): 537-8, 562).

11 Thomas, ST, Ia.29.1 and 3, 327-8, 331-2.  Cf. Ia.30.1 ad 1, 336.

12 Again, if two or more are “really” identical, this means they are one and the same as to “thing” or “being.”  They may still be distinct in various other ways within that one being.  In addition, Thomas and other scholastic theologians will sometimes call two things “really” distinct when they mean not that they are two “things” or “beings” in the strict sense but that they are in some way distinct in reality and not just in the human mind.

13 Cf. Gilles Emery, The Trinitarian Theology of St Thomas Aquinas (trans. Francesca Aran Murphy; Oxford: Oxford University Press, 2007), 117-18, 121.

14 See Augustine, The Trinity (trans. Edmund Hill; Hyde Park: New City Press, 1991), V.2.10, 196.

15 Thomas, ST, Ia.29.4 corp. and ad 1, 333-4.  Cf. Ia.39.1 corp. and ad 1, 396.  Thomas thus acknowledges, with Augustine, that persona can designate the Father, Son and Spirit ad se (with respect to what they are, without primary emphasis on their mutual relations) rather than just ad alterum (with respect to their mutual relations alone).

16 Thomas, ST, Ia.32.3 corp., 355.

17 Thomas, ST, Ia.32.2 corp. and ad 2, 351-2; 40.1 corp. and ad 1-2, 411-12.

18 See Thomas, De Pot., II.2, 27-9; II.4 ad 1-2, 33; ST, Ia.41.5, 430.

19 Thomas, ST, Ia.33.1, 358.

20 However modern translators might wish to render the Greek word harpagmos in Philippians 2:6, the point remains: the Son was and is fully equal to the Father in his deity.

21 Donantis auctoritate Pater major est, sed minor non est cui unum esse donatur.

22 Thomas, ST, Ia.42.4 corp. and ad 1 and 2, 441.  Michael Waldstein (“The Analogy of Mission and Obedience: A Central Point in the Relation between Theologia and Oikonomia in St. Thomas Aquinas’s Commentary on John,” in Reading John with St. Thomas Aquinas (ed. Michael Dauphinais and Matthew Levering; Washington, D.C.: Catholic University of America Press, 2005), 104 et passim) contends that Thomas’s comments here (and in various places in his commentary on John’s Gospel) come “quite close” to ascribing obedience to the Son in his divinity.  In my view, Thomas is speaking in a loose manner when he grants that the Son’s subjection to the Father’s auctoritas may pertain to his procession from the Father.  It seems to me that Thomas is indicating that the language may be taken to refer back to the Son’s procession and reception of the essence from the Father without importing a concept of subjection or obedience in any strict or common sense back into the Son’s eternal relation to the Father.

23 Thomas Aquinas, ST, Pars Tertia, in Opera Omnia (vol. 11; Leonine ed.; Rome: ex Typographia Polyglotta, 1903), IIIa.20.1 corp. and ad 1, 247-8.  Consistent in his affirmation that divinity entails lordship (as opposed to servanthood), Thomas is prepared to say that Christ in his human nature is subject to himself in his divine nature (without this implying two persons) (ST, IIIa.20.2 corp., 249).

24 Strictly speaking, the Father and Son share the same being (esse), which is really identical to the essence they share.  They do not, then, have distinct “existences” but only distinct modes of subsisting within the divine essence and existence (cf. De Pot., II.1 corp., 25).  However, one can say that the Son receives the divine esse from the Father by generation.

25 Thomas Aquinas, Super Evangelium S. Ioannis Lectura (5th ed.; ed. Raffaele Cai; Turin-Rome: Marietti, 1952), V.3.1.746-51, 140-1.  ET: Commentary on the Gospel of John Chapters 1-5 (trans. Fabian Larcher and James A. Weisheipl; Washington, D.C.: Catholic University of America Press, 2010). Cf. ST, Ia.42.6 ad 1 and 2, 444.  In Thomas’s judgment, Christ uses the language of “seeing” and “showing” in this text simply because these are common ways in which we receive knowledge.  Also, as noted above, according to Thomas, the Father’s communication of knowledge and power to the Son is a matter of the Father generating not a second version of the divine essence and absolute attributes in the Son but rather the Son who with him shares in the one divine essence and absolute attributes.

26 Thomas, Super Evangelium S. Ioannis, V.4.1.755-4.769, 143-5.

27 Thomas, Super Evangelium S. Ioannis, V.5.4.794-5.798, 150-1.  To say that the Son exercises the divine will as he has it “from the Father” is very different from saying that the Son as God or under his eternal relation to the Father submits to the will of the Father.  The former is simply an implication of the eternal generation of the Son; the latter, however, would imply that the Son has a distinct divine willing and acting of his own in which he would respond to an antecedent decision of the Father, and the fact that the Son shares the one divine will and action with the Father (and Spirit) precludes such an arrangement of “functional subordination” in the Trinity.

28 Indeed, while Thomas recognizes that certain outward works of God are only “appropriated” to the Son (attributed to the Son on account of some analogy between the character of the work and the proper character of the person of the Son), he recognizes this mode of working “from the Father” to be itself “proper” to the Son (Super Evangelium S. Ioannis, I.2.1.76, 17; ST, Ia.39.8 corp., 410).

29 Thomas, ST, Ia.43.1 corp. and ad 1, 445; 43.2 corp. and ad 3, 446.

30 Thomas, ST, Ia.43.4, 449.  Because of his commitment to the unity of the action of the Father, Son and Spirit, Thomas is willing to affirm that the Son, in a qualified sense, sends himself in the economy.  On the one hand, if the sender is considered with respect to him being the principle of the person sent, then the sender should be identified as just the person from whom the one sent eternally proceeds.  In that respect, only the Father sends the Son.  On the other hand, if the sender is considered with respect to him being the principle of the temporal effect of the mission, then, since all three persons together accomplish God’s outward works, all three persons may be said to have sent the one who is sent (Ia.43.8 corp., 454).

31 Thomas, ST, IIIa.3.5 corp. and ad 1 and 3, 63.  Thomas still holds the incarnation of the Son to be “fitting” in a number of significant ways (on which, see Matthew Levering, “Christ, the Trinity, and Predestination: McCormack and Aquinas,” in Trinity and Election in Contemporary Theology (ed. Michael T. Dempsey; Grand Rapids: Eerdmans, 2011), 252-71).

32 For different appraisals of Barth on the Son’s obedience, see Paul D. Molnar, “The Obedience of the Son in the theology of Karl Barth and of Thomas F. Torrance,” Scottish Journal of Theology 67 (2014): 50-69;Darren O. Sumner, “Obedience and Subordination in Karl Barth’s Trinitarian Theology,” in Advancing Trinitarian Theology: Explorations in Constructive Dogmatics (ed. Oliver D. Crisp and Fred Sanders; Grand Rapids: Zondervan, 2014), 130-146.  It is a matter of debate in Barth studies today whether he eventually reached the conclusion that God in fact could not and would not have been God without choosing to create the world and save sinners in the incarnation.  On this, see, e.g., Bruce L. McCormack, “Grace and Being,” in The Cambridge Companion to Karl Barth (ed. John Webster; Cambridge: Cambridge University Press, 2000), 92-110; “Processions and Missions: A Point of Convergence between Thomas Aquinas and Karl Barth,” in Thomas Aquinas and Karl Barth: An Unofficial Catholic-Protestant Dialogue (ed. Bruce L. McCormack and Thomas Joseph White; Grand Rapids: Eerdmans, 2013), 99-126; Dempsey, ed., Trinity and Election;Paul D. Molnar, Faith, Freedom and the Spirit: The Economic Trinity in Barth, Torrance and Contemporary Theology (Downers Grove: InterVarsity Press, 2015); George Hunsinger, Reading Barth with Charity: A Hermeneutical Proposal (Grand Rapids: Baker, 2015).

33 Karl Barth, Church Dogmatics (ed. G. W. Bromiley and T. F. Torrance; trans. G. W. Bromiley et al.; London: T & T Clark, 2009), IV.1, 192 (hereafter CD).

34 Barth, CD,IV.1, 159.

35 Barth, CD, IV.1, 177.

36 Barth, CD, IV.1, 177, 179-80, 183-7.

37 Barth connects this approach to the Sabellian heresy.

38 Barth believes those who assume that subordination entails inferiority are thinking in an “all too human” way about God.  Given this caution about anthropomorphism, it is perhaps surprising that Barth does seem to accept that the “self-evident presupposition that a son owes obedience to a father” applies in the case of God (CD, IV.1, 202, 209-10).

39 Barth, CD, IV.1, 193, 195-210.

40 E.g., Jerome Zanchi, De Incarnatione Filii Dei (Heidelberg, 1593), I.3, 52; Peter van Mastricht, Theoretico-Practica Theologia (2nd ed.; Utrecht, 1724), II.26.18, 258.

41 E.g., Bartholomäus Keckermann, Systema S. S. Theologiae, in Operum Omnium quae Extant (vol. 2; Geneva, 1614), I.4, p. 94; Amandus Polanus, Syntagma Theologiae Christianae (Hanoviae, 1615), VI.13, 364; Francis Turretin, Institutes of Elenctic Theology (vol. 1; ed. James T. Dennison, Jr.; trans. George Musgrave Giger; Phillipsburg: P & R Publishing, 1992), III.15.12, 269; Wilhelmus à Brakel, The Christian’s Reasonable Service (vol. 1; Grand Rapids: Reformation Heritage, 1992), I.4, 175;Mastricht, Theoretico-Practica Theologia, II.26.18, 258.

42 On this development, see Carl Trueman, “From Calvin to Gillespie on Covenant: Mythological Excess of Doctrinal Development?,” International Journal of Systematic Theology 11 (2009): 378-97.

43 Johannes Coccejus, Summa Doctrinae de Foedere et Testamento Dei (Amsterdam, 1688), V.88, 85-7; 89, 89; 91-3, 91-2; 94-5, 94.  ET: The Doctrine of the Covenant and Testament of God (trans. Casey Carmichael; Grand Rapids: Reformation Heritage, 2016).

44 Herman Witsius, Exercitationes Sacrae in Symbolum quod Apostolorum dicitur (2nd ed.; Franeker, 1689), VII.20, 102; 22-3, 103.  ET: Sacred Dissertations on the Apostles’ Creed (2 vols.; trans. Donald Fraser; Grand Rapids: Reformation Heritage, 2012).

45 Herman Witsius, De Oeconomia Foederum Dei cum Hominibus (2nd ed.; Leeuwarden, 1685), II.3.4-9, 113-14; 21, 117.  ET: The Economy of the Covenants between God and Man (2 vols.; trans. William Crookshank; Grand Rapids: Reformation Heritage, 2012).

46 Divina quoque ejus natura in subjectionis hujus consortium trahatur.

47 Witsius, Oeconomia Foederum, II.3.16-20, 115-17.

48 Zanchi, De Incarn., II.3, 95-8.

49 Francis Turretin, Institutes of Elenctic Theology (vol. 2; ed. James T. Dennison, Jr.; trans. George Musgrave Giger; Phillipsburg: P & R Publishing, 1992), XIII.4.5-6, 304-5.

50 Steven Boyer (“Articulating Order: Trinitarian Discourse in an Egalitarian Age,” Pro Ecclesia 18 (2009): 265-7) suggests that the distinct modes in which the Father and Son have and exercise the divine will might be rendered in terms of “command” and “obedience” within a “single, shared volition.”  But the submission revealed to us in Scripture pertains to the economy; Scripture does not invite us to posit command and obedience in the processions and constitutive relations of the persons.  Human sons are surpassed by human fathers in age and experience and (we hope) in wisdom, moral fortitude and strength and so are in this way less than and obedient to human fathers.  None of this applies in the eternal processions in God.  It is crucial, then, to avoid reading the economic dynamic of obedience back into God’s own triune being.  Scott Swain and Michael Allen (“The Obedience of the Eternal Son,” International Journal of Systematic Theology 15 (2013): 125-8, 130-1) also appear to interpret the Son’s proper mode of willing and acting as a matter of divine obedience to the Father and adduce Thomas’s commentary on John 5:30 in support this view.  However, as noted above, in his comments on John 5:30, Thomas says that if the text pertains to Christ as man, then it would involve obedience, but if it pertains to Christ as the divine Son, then it would witness to the fact that the Son has the divine will from the Father by generation.  In other words, for Thomas, the options are either (human) obedience or divine willing according to the Son’s proper mode, not divine willing from the Father as itself obedience.

51 See Barth, CD, IV.1, 184.

52 For an attempt to flesh out the latter, see Thomas Joseph White, “The Voluntary Action of the Earthly Christ and the Necessity of the Beatific Vision,” The Thomist 69 (2005): 522-33 and “Intra-Trinitarian Obedience and Nicene-Chalcedonian Christology,” Nova et Vetera 6 (2008): 397-401.