Catechism of the Catholic Church §981 — excerpt
After his Resurrection, Christ sent his apostles "so that repentance and forgiveness of sins should be preached in his name to all nations." The apostles and their successors carry out this "ministry of reconciliation," not only by announcing to men God's forgiveness merited for us…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Augustine, Sermo 214, 11: PL 38, 1071-1072