How is the body to become a sacrifice? Let the eye look on no evil thing, and it has already become a sacrifice. Let the tongue say nothing filthy, and it has become an offering. Let your hand do nothing evil, and it has become a whole burnt offering. But even this is not enough for we must have good works also. The hand must do alms, the mouth must bless those who curse it, and the ears must find time to listen to the reading of Scripture. Sacrifice allows no unclean thing. It is the first fruits of all other actions.

—John Chrysostom, Homilies on Romans 20