Biblical theology helps us get our arms around the big picture that ties together everything from Leviticus to Esther, and we see how Amos, John, Romans, and Revelation fit, too. Knowing what the forest looks like enables understanding of the individual trees. If we are to preach the whole counsel of God, we need biblical theology.
What sets the agenda in your preaching? Nehemiah really is not about the building program some church wants to initiate, and the Psalms are not in the Bible for amateur psychotherapists to explore their inner depths from the pulpit. Has God communicated His agenda in the Bible’s big story—its overarching message? Does the Bible’s big story set the agenda for your preaching or does something else drive it? If we are going to understand God’s purposes, which are revealed in the Bible, we need biblical theology.
Biblical theology pushes us to understand the contribution individual books of the Bible make to the Bible’s big story. We might call the Bible’s big story its metanarrative. However we describe it, the point is that the whole Bible fits together to tell us God’s revealed story of where the world came from, what is wrong with it, what He is doing to fix it, where we t in the program, and what we can expect in the near and distant future. But there is a greater end to all this information: God is revealing Himself to us. We need biblical theology to know God. Knowing God fuels worship. Biblical theology is for worship.