Not by way of reason, but only by way of love and suffering, do we come to the living God, the human God. Reason rather separates us from Him. We cannot first know Him in order that afterward we may love Him; we must begin by loving Him, longing for Him, hungering after Him, before knowing Him. The knowledge of God proceeds from the love of God, and this love has little or nothing of the rational in it. For God is indefinable. To seek to define Him is to seek to confine Him within the limits of our mind — that is to say, to kill Him. In so far as we attempt to define Him, there rises up before us — Nothingness.

The Tragic Sense of Life (1913) - VIII : From God to God