God calls us to know Him, but tells us he is unknowable. He calls us to walk with him, but he is wholly other. These tensions -- and the faith contains many tensions -- once frustrated me. Now they invigorate me.
I love what he says of himself in Isaiah 55:8 & 9. In the NIV, the verses read, "For my thoughts are not your thoughts, neither are your ways my ways," declares the LORD. As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts."
This liberates me as I study and meditate on the Lord and his word. This liberates me from totally understanding the Trinity, or the dual natures of Christ, or free will and the chosen. I cling to those 2 verses in Isaiah when my mind gets stuck trying to unravel one theological paradox or another.
These verses have taught me how small I am in comparison to him. And they have taught me to be suspicious of any theology that seems too easy. If I could understand God, he wouldn't be much of a God, would he?