What Can We Know about God?

Such knowledge is too wonderful for me, too lofty for me to attain. [Ps. 139:6]

Protestantism has at the heart of its theory the doctrine of the incomprehensibility of God. But this word incomprehensible in theology does not mean what the term itself might suggest at first glance. It does not mean that God is utterly unknowable; rather it is meant to indicate that no one can comprehend God exhaustively. None of us has total, comprehensive, exhaustive knowledge of who God is or what his character is like.
A very important formula came out of the sixteenth-century Reformation: “The finite cannot contain or grasp the infinite.” We can approach an understanding of the concept of incomprehensibility first by thinking about the idea of “containment.”
Could we squeeze the infinite God into a finite space? Clearly not, because if we could, God would no longer be infinite. The finite can never contain or envelop the infinite.
Since we are finite creatures, our minds always work from a finite perspective. So we can never understand God fully, because God lives and moves and has his being on an infinite plane, while we live and move and have our being on a finite plane. The finite cannot grasp or contain the infinite. Therefore, in theological terms we say God is incomprehensible.
That concept is very important to our understanding because it represents a check and balance—a corrective—to warn us in case any of us think we have altogether mastered every detail regarding the things of God. We know that, however we understand God, our capacity to comprehend him is limited by our own finitude. He is the Creator. We are created beings.
Sproul, R.C., Before the Face of God: A Daily Guide for Living from the Book of Romans, (Grand Rapids, MI: Baker Books) 1992.