Roman Catechism 19.39

Chapter 19 — Part II: The Sacraments — Penance

Section 39. Effects of the Sacrament of Penance — Nothing will prove of greater advantage to the faithful, nothing will be found to conduce more to a willing reception of the Sacrament of Penance, than for pastors to explain frequently the great advantage to be derived therefrom. They will then see that of Penance it is truly said that its roots ale bitter, but its fruit sweet indeed.