Chapter 19 — Part II: The Sacraments — Penance
Section 33. Moreover, since the Sacraments signify what they effect, the words, I absolve thee, signify that remission of sin is effected by the administration of this Sacrament; and hence it is plain that such is the perfect form of the Sacrament. For sins are, so to say, the chains by which the soul is bound, and from which it is freed by the Sacrament of Penance. And none the less truly does the priest pronounce the form over the penitent who, through perfect contrition, accompanied by the desire of confession, has already obtained remission of his sins from God.