Roman Catechism 19.169

Chapter 19 — Part II: The Sacraments — Penance

Section 169. This, however, is not true in reference to all the advantages to be derived from satisfaction. For works of satisfaction are also medicinal, and are so many remedies prescribed to the penitent to heal the depraved affections of the soul. It is clear that those who do not satisfy for themselves can have no share in this fruit of penance.