From The Cost of Discipleship by Dietrich Bonhoeffer, quoting Martin Luther. I got this from "On the Way."
Plunge Into Deep Waters
Martin Luther
Discipleship is not limited to what you can understand - it must transcend all comprehension. Plunge into the deep waters beyond your own understanding.... Bewilderment is the true comprehension. Not to know where you are going is the true knowledge. In this way Abraham went forth from his father, not knowing where he was going. You cannot find it in yourself, so you must let me lead you as though you were a blind man. Not the work which you choose, not the suffering you devise, but the road which is contrary to all that you choose or contrive or desire - that is the road you must take.
