" The otherworldliness of the Christian life ought, Luther concluded, to be manifested in the very midst of the world, in the Christian community and in its daily life. Hence the Christian's task is to live out that life in terms of his secular calling. That is the way to die unto the world. The value of the secular calling for the Christian is that it provides an opporunity of living the Christian life with the support of God's grace, and of engaging more vigorously in the assault on the world and everything that it stands for. Luther did not return to the world because he had arrived at a more positive attitude towards it. Nor had he abandoned the eschatological expectation of early Christianity. He intended his action to expres a radical criticism and protest against the secularization of Chrisitanity which had taken place within monasticism. By recalling the Christians into the world he called them paradoxically out of it all the more. That was what Luther experienced in his own person. His call to men to return to the world was essentially a call to enter the visible Church of the incarnate Lord. "

― Dietrich Bonhoeffer , The Cost of Discipleship