At the end of a life spent in the pursuit of knowledge Faust has to confess: “I now do see that we can nothing know.” That is the answer to a sum, it is the outcome of a long experience. But as Kierkegaard observed, it is quite a different thing when a freshman comes up to the university and uses the same sentiment to justify his indolence. As the answer to a sum it is perfectly true, but as the initial data it is a piece of self-deception. For acquired knowledge cannot be divorced from the existence in which it is acquired. The only man who has the right to say that is justified by grace alone is the man who has left all to follow Christ.
–“The Cost of Discipleship” by Dietrich Bonhoeffer