Chapter 19 — Part II: The Sacraments — Penance
Section 15. That penance is a virtue may also be inferred from the ends which the true penitent proposes to himself. The first is to destroy sin and efface from the soul its every spot and stain. The second is to make satisfaction to God for the sins which he has committed, which is clearly an act of justice. Between God and man, it is true, no relation of strict justice can exist, so great is the distance that separates them; yet between them there is evidently a sort of justice, such as exists between a father and his children, between a master and his servants. The third (end of the penitent) is to reinstate himself in the favour and friendship of God whom he has offended and whose hatred he has earned by the turpitude of sin. The foregoing considerations sufficiently prove that penance is a virtue.