What is Biblical Theology?

All good preaching takes into account biblical theology, but we have to ask first what biblical theology is and how it differs from systematic theology. The first thing to be said is that biblical and systematic theology overlap. That is the nature of life; things can’t be put into tight compartments hermetically sealed off from one another. Still, biblical theology focuses on the history of redemption, the time-line of the biblical story, the progress of redemption throughout history. Biblical theology always asks as we interpret each book of the Bible where we are in the storyline of the Bible. Systematic theology, on the other hand, considers the doctrines taught in the Scriptures as well, asking what the entire Bible teaches about the Trinity, angels, human beings, salvation, the church, the last things, etc. All good preaching, then, includes both biblical and systematic theology. Of course, there is no formula for how we do this as we preach particular texts. But we always keep in mind both biblical and systematic theology as we are preaching.

Where are we in the storyline?

When we preach from the scriptures, we need to pay attention to where we are in the biblical story. For instance, if we are preaching from Exodus, we must consider what we have already learned from Genesis. For example, when Exodus begins we see that Israel is growing remarkably in terms of its population. Such growth, if we are reading in terms of the whole story, clearly fulfills the covenant made with Abraham which promises that the Abraham’s children will be as many as the stars of the sky. Similarly, when the prophets indict Israel for its sin, the judgments inflicted are on the basis of the covenant made with Israel under Moses. Judgments are poured out in Israel because they have violated the covenant stipulations made with the nation. Or, the many promises in the prophets about a coming king should be traced back to the covenant pledge made to David, that there would always be a king coming from the line of David. In every case, we read the scriptures in light of the developing story line. That continues, of course, in the New Testament. When we read that Jesus is the Messiah, we understand his messianic ministry in light of the covenant made with David.

Canonical Reading

Canonical reading is really another way really of thinking about the story line in the Bible. Still, here we emphasize that the Old Testament must be read in light of New Testament revelation. For instance, how should we preach Leviticus 1–7 which describe the Old Testament sacrifices required in the tabernacle? Certainly, we can only preach those chapters in light of what Jesus Christ has accomplished. The lesson for our hearers is not that we should offer sacrifices at the temple, although there is no temple any longer where sacrifices may be offered! We read those chapters in light of the sacrifice of Christ, and preach that he is the final and definitive sacrifice.
Along the same lines, we read in Exodus 12–14 that Israelites were to remove leaven from their houses during the festivals of Passover and Unleavened Bread. How do we preach that text today? We read the text both canonically and in terms of redemptive history. It would be quite strange if we were to preach the historic meaning of the text, if we were to say that God desires us to remove leaven from our homes for one week during the year. We see in 1 Corinthians 5:6–8, however, that Christ is our Passover sacrifice and we are to remove the leaven of malice and wickedness in our lives. That is the message we are to preach when we study Exodus 12–14.

Or think of the command that evil must be purged from the midst of Israel (Deut. 17:7; 19:19; 21:21; 22:21, 22, 24; 24:7; cf. Deut. 13:5). This command applies in criminal cases, where Israel must put to death those guilty of idolatry (Deut. 17:7), a stubborn and rebellious son (Deut. 21:21), those engaged in sexual sin (Deut. 22:21, 22, 24) kidnappers (Deut. 24:7), and false witnesses (Deut. 19:19). Should we apply the same criterion today and put to death malefactors? Certainly not. Paul cites this very command in 1 Cor. 5:13, but he doesn’t argue that the man committing incest should be put to death. He mandates that he should be excommunicated from the church. Paul appropriates the Old Testament command to purge evil from the congregation both redemptive historically and canonically. He reads the text in light of the fulfilment that has come in Jesus Christ, and he reads it covenantally. Believers are no longer under the covenant made with Israel which was a theocracy. The church is not a nationalistic state, and no single nation is God’s chosen people. Now believers come from every nation, and the church remains pure not by removing from their fellowship those who have forsaken the gospel.

We see then that biblical theology is crucial for interpreting the Bible because if one fails to pay heed to biblical theology the text of the Bible will be interpreted in wooden and even damaging ways. We must always interpret the scriptures in light of the biblical storyline and the fulfillment that has come in Jesus.