Luther

“Now, therefore, let me describe in order four groups of people. The first are those whose entire interest is in the words of this sacrament, so that they feed their faith; they receive the bread and wine with the body and blood of Christ as a sure sign of that word and faith. These are the most secure and the best. They probably seldom descend so low as to bother themselves about worshiping and adoring, for they pay attention to the work God does to them and forget about the works they do for the sacrament.

     The second group are those who exercise the right sort of faith, and then descended to their own works and worship Christ spiritually in the sacrament. That is, they bow inwardly with their hearts and confess him as their Lord, who does all things within them; and they prove their inward worship by outwardly bowing, bending, and kneeling with the body.” Martin Luther, The Adoration of the Sacrament, LW, AE, 36:296