Catechism of the Catholic Church
1446 Christ instituted the sacrament of Penance for all sinful members of his Church: above all for those who, since Baptism, have fallen into grave sin, and have thus lost their baptismal grace and wounded ecclesial communion. It is to them that the sacrament of Penance offers a new possibility to convert and to recover the grace of justification. The Fathers of the Church present this sacrament as "the second plank [of salvation] after the shipwreck which is the loss of grace." 47
1447 Over the centuries the concrete form in which the Church has exercised this power received from the Lord has varied considerably. During the first centuries the reconciliation of Christians who had committed particularly grave sins after their Baptism (for example, idolatry, murder, or adultery) was tied to a very rigorous discipline, according to which penitents had to do public penance for their sins, often for years, before receiving reconciliation. To this "order of penitents" (which concerned only certain grave sins), one was only rarely admitted and in certain regions only once in a lifetime. During the seventh century Irish missionaries, inspired by the Eastern monastic tradition, took to continental Europe the "private" practice of penance, which does not require public and prolonged completion of penitential works before reconciliation with the Church. From that time on, the sacrament has been performed in secret between penitent and priest. This new practice envisioned the possibility of repetition and so opened the way to a regular frequenting of this sacrament. It allowed the forgiveness of grave sins and venial sins to be integrated into one sacramental celebration. In its main lines this is the form of penance that the Church has practiced down to our day.
1448 Beneath the changes in discipline and celebration that this sacrament has undergone over the centuries, the same fundamental structure is to be discerned. It comprises two equally essential elements: on the one hand, the acts of the man who undergoes conversion through the action of the Holy Spirit: namely, contrition, confession, and satisfaction; on the other, God's action through the intervention of the Church. The Church, who through the bishop and his priests forgives sins in the name of Jesus Christ and determines the manner of satisfaction, also prays for the sinner and does penance with him. Thus the sinner is healed and re-established in ecclesial communion.
1449 The formula of absolution used in the Latin Church expresses the essential elements of this sacrament: the Father of mercies is the source of all forgiveness. He effects the reconciliation of sinners through the Passover of his Son and the gift of his Spirit, through the prayer and ministry of the Church:
God, the Father of mercies,
through the death and the resurrection of his Son
has reconciled the world to himself
and sent the Holy Spirit among us
for the forgiveness of sins;
through the ministry of the Church
may God give you pardon and peace,
and I absolve you from your sins
in the name of the Father, and of the Son and of the Holy Spirit. 48
English Translation of the Cathechism of the Catholic Church for the United States of America © 1997, United States Catholic Conference, Inc.