What is biblical theology? In simplest terms, it means theology that comes from the Bible. More specifically, biblical theology studies the theology of the Bible according to its own terms, themes, and storyline. It then tries to understand the various theological themes across the whole canon of the Bible to discover shared meaning among Scripture’s diversity.
In this sense, biblical theology provides theological first principles that systematic theology may use to expose the underlying structures of created and uncreated reality. Definitions like these often feel abstract or vague. One way to understand biblical theology with more clarity is to know its limitations since we often learn by contrasts. The limitations include the following:
First, biblical theology isolates itself from systematic theology
Since biblical theology (BT) uses the language, idioms, structures of the biblical revelation, it excludes some post-biblical reflection. Put another way, BT does not have a necessary place for words like Trinity or original sin. It instead uses words like “chosen people,” “the mountain,” and “fire.”
Biblical theology leaves some post-biblical reflection to systematic theology (ST). In other words, BT provides first principles of theology that ST organizes and speculates about. Hence, BT has built-in limitations to what it can do.
Second, biblical theology cannot define the centre of Scripture
Biblical theologians try to discover the centre of Scripture. Yet they have not succeeded, which is obvious since every BT book proposes different centres or ones too abstract to be of real interpretive use. If BT had discovered a central theme or idea, then more people could identify it with clarity and persuasiveness. None have. None will.
This is not to say that Scripture has no centre. It does. But the methods of BT cannot uncover it. Considering the following illustration to explain why BT cannot do so. Imagine that the Old Testament is a painting. The canvas displays a detailed background and outline of a central image. Yet the image at the centre simply is not there; a veil drapes over it. It displaces the rest of the picture, yet demands to be filled in.
It takes an unveiling to see it. That unveiling or revelation happens when Christ reveals himself to the world. He is uncovered. The whole painting now makes sense. The displaced parts not feel in place. What was hidden is now revealed. And apart from seeing this image no one will be able to inductively grasp the centre when reading the Old Testament Scriptures.
Hence, Paul speaks of “the revelation of the mystery that was kept secret for long ages but has now been disclosed” (Rom 16:25–26). Due to the revelation of Jesus Christ, the Spirit teaches Christians to see the central scriptural picture of the Old Testament.
In this sense, BT’s methodology of using the Bible’s own terms, themes, and storyline may try to show an organic connection from the Old Testament to Christ. Yet it can only do so from the perspective of the cross. One must read backwards to make sense of the beginning. The methodology of BT often precludes or at least downplays such a deductive move.
Third, biblical theology tends to avoid metaphysical thinking
The Bible is full of metaphysical notions. One only has to read Exodus 24 to see the threefold ascent of Moses into middle heaven and the highest heaven. The Pentateuch itself portrays the tabernacle as an earthly symbol of a heavenly reality. Much more could be said (and should!). Yet interestingly BT tends to avoid metaphysical thinking.
The reason why is obvious after it is considered. Systematic theology tends to think metaphysically to uncover seen and unseen realities that biblical and natural revelation reveal. In one sense, metaphysical reasoning (at least traditionally) falls to ST.
All of this leads to a larger problem between the divide of BT and ST. In previous ages, these disciplines often were united. Most biblical commentaries of the past focused on both philology and theology. Yet the splitting of theology (ST) from history (BT) has crippled both disciplines by creating artificial barriers and limits.
Some have tried to overcome the divide by emphasizing that we ought to do theological interpretation of Scripture (TIS). The idea is correct, but the movement is so diverse that it can be hard to endorse.
With all of that said, I enjoy BT and ST, but I am moving to increasingly integrated way of reading Scripture that approximates TIS—with the caveat that I cannot endorse much of what comes under the form of TIS.
So enjoy and benefit from BT but know its limits. Enjoy ST but knows its limits. And I would say: move towards an integrated biblical and systematic approach to Scripture to uncover the deeper structures of unseen and seen realities through biblical and natural revelation.