PENANCE
Penance is a Sacrament whereby the sins, whether mortal or venial, which we have committed after Baptism are forgiven. It is also called the Sacrament of Reconciliation, the Sacrament of Forgiveness, the sacrament of Confession, and the Sacrament of Conversion. (C/f CCC Compendium 296). Those who approach the Sacrament of Penance obtain pardon from God’s mercy for the offense committed against him, and are, at the same time, reconciled with the Church which they have wounded by their sins and which by charity, by example and by prayer labours for their conversion. (C/f CCC 1422). Penance is raised to the status of Sacrament following the command of Christ to his Apostles when on the evening of that day, the first day of the week, Jesus showed himself to his apostles. He breathed on them, and said to them: ‘Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained’ [Jn. 20: 19, 22-23] (C/f CCC 1485). Hence, only priests who have received the faculty of absolving from the authority of the Church can forgive sins in the name of Christ. (C/f CCC 1495).
Furthermore, in the sacrament of penance the faithful who confess their sins to a lawful minister, are sorry for those sins and have a purpose of amendment, receive from God, through the absolution given by that minister, forgiveness of sins they have committed after baptism, and at the same time they are reconciled with the Church, which by sinning they wounded (Can. 959).