A Christian epistemology does not begin its systematic approach to theology and philosophy with a discussion of whether there is a god or how we know there is a god, and then seek to prove that this is the God of Scripture. The starting point in a genuine Christian epistemology is revelation. The doctrine of God follows epistemology. This is why the Westminster Assembly began its study of systematic theology with the doctrine of revelation. Chapter 1 of the Westminster Confession of Faith has to do with our source of knowledge: “Of the Holy Scripture.” The following 32 chapters are erected upon the axiom of Biblical revelation.
W. Gary Crampton, Scripturalism: A Christian Worldview
God as distinct from Scripture is not made the axiom of this argument. Undoubtedly this twist will seem strange to many theologians. It will seem particularly strange after the previous emphasis on the mind of God as the origin of all truth. Must not God be the axiom? For example, the first article of the Augsburg Confession gives the doctrine of God, and the doctrine of the Scripture hardly appears anywhere in the whole document. In the French Confession of 1559, the first article is on God; the Scripture is discussed in the next five. The Belgic Confession has the same order. The Scotch Confession of 1560 begins with God and gets to the Scripture only in article nineteen. The Thirty-Nine Articles begin with the Trinity, and Scripture comes in articles six and following. If God is sovereign, it seems very reasonable to put him first in the system.
But several other creeds, and especially the Westminster Confession, state the doctrine of Scripture at the very start. The explanation is quite simple: our knowledge of God comes from the Bible. We may assert that every proposition is true because God thinks it so, and we may follow Charnock in all his great detail, but the whole is based on Scripture. Suppose this were not so. Then “God” as an axiom, apart from Scripture, is just a name. We must specify which God. The best known system in which “God” was made the axiom is Spinoza’s. For him all theorems are deduced from Deus sive Natura. But it is the Natura that identifies Spinoza’s God. Different gods might be made axioms of other systems. Hence the important thing is not to presuppose God, but to define the mind of the God presupposed. Therefore the Scripture is offered here as the axiom. This gives definiteness and content, without which axioms are useless.
Gordon H. Clark, God and Logic
We also thought it was important to begin our confession with God rather than with Scripture. This is significant. The Enlightenment was overconfident about human rationality. Some strands of it assumed it was possible to build systems of thought on unassailable foundations that could be absolutely certain to unaided human reason. Despite their frequent vilification of the Enlightenment, many conservative evangelicals have nevertheless been shaped by it. This can be seen in how many evangelical statements of faith start with the Scripture, not with God. They proceed from Scripture to doctrine through rigorous exegesis in order to build (what they consider) an absolutely sure, guaranteed-true-to-Scripture theology.
The problem is that this is essentially a foundationalist approach to knowledge. It ignores the degree to which our cultural location affects our interpretation of the Bible, and it assumes a very rigid subject-object distinction. It ignores historical theology, philosophy, and cultural reflection. Starting with the Scripture leads readers to the overconfidence that their exegesis of biblical texts has produced a system of perfect doctrinal truth. This can create pride and rigidity because it may not sufficiently acknowledge the fallenness of human reason.
We believe it is best to start with God, to declare (with John Calvin, Institutes1.1) that without knowledge of God we cannot know ourselves, our world, or anything else. If there is no God, we would have no reason to trust our reason.
D.A. Carson & Tim Keller Gospel-Centered Ministry