There are two practices, penance and mortification. The actions of both are the same, although the reason differs. Mortification is to help us stay away from sin as Saint. Paul said: "But I chastise my body, and bring it into subjection: lest perhaps, when I have preached to others, I myself should become a castaway." [1 Corinthians 9:27] Penance is for penitents, which we consider an act only penitents can do. Do any of us think of giving up sin?