Chapter 19 — Part II: The Sacraments — Penance
Section 173. Quantity And Quality Of Penances Should Be Reasonable — In imposing penance priests should do nothing arbitrarily, but should be guided solely by justice, prudence and piety. In order to show that they follow this rule, and also to impress more deeply on the mind of the penitent the enormity of his sin, it will be useful sometimes to remind him of the severe punishments inflicted by the ancient penitential canons, as they are called, for certain sins. The nature of the sin, therefore, will regulate the extent of the satisfaction.