'The most experienced psychologist or observer of human nature knows infinitely less of the human heart than the simplest Christian who lives beneath the Cross of Jesus. The greatest psychological insight, ability, and experience cannot grasp this one thing: what sin is. Worldly wisdom knows what distress and weakness and failure are, but it does not know the godlessness of men. And so it also does not know that man is destroyed only by his sin and can be healed only by forgiveness. Only the Christian knows this. In the presence of a psychiatrist I can only be a sick man; in the presence of a Christian brother I can dare to be a sinner. The psychiatrist must first search my heart and yet he never plumbs its ultimate depth. The Christian brother knows when I come to him: here is a sinner like myself, a godless man who wants to confess and yearns for God's forgiveness.'
Dietrich Bonhoeffer, Life Together, p.93.