“Luther laid the greatest emphasis of all on the fact that everything must be done freely and joyfully. At the very beginning of he Psalms Lectures we find references to the free, the joyful, the spontaneous will. God desires no forced service. Whatever action does not arise spontaneously from within, but is forced for a specific purpose at a particular moment, will not last; it is no real act of the will, and has no value at all in the eyes of God. ”
Karl Holl The Reconstruction of Morality p. 34