Through the sacraments of Christian initiation, we receive the new life of Christ. Now, we carry this life “in earthen vessels,” and it remains “hidden with Christ in God.” We are still in our “earthly tent,” subject to suffering, illness, and death. This new life as a child of God can be weakened and even lost by sin. (CCC 1420) 

Sin is before all else an offense against God, a rupture of communion with Him. At the same time, it damages communion with the Church. (CCC 1440) Thus, Christ Jesus instituted the sacrament of Penance & Reconciliation 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.” (CCC 1446) 

The Lord Jesus Christ, physician of our souls and bodies, who forgave the sins of the paralytic and restored him to bodily health, has willed that His Church continue, in the power of the Holy Spirit, His work of healing and salvation, even among her own members. This is the purpose of the two sacraments of healing: the sacrament of Penance & Reconciliation and the sacrament of Anointing of the Sick. (CCC 1421) 

The sacrament of Penance & Reconciliation obtains 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 labors for their conversion. (CCC 1422) 

It is called the sacrament of confession since the disclosure or confession of sins to a priest is an essential element of this sacrament, i.e. acknowledgment and praise – of the holiness of God and of His mercy toward sinners. It is called the sacrament of forgiveness, since by the priest’s sacramental absolution, God grants the penitent “pardon and peace.” It is called the sacrament of Reconciliation, because it imparts to the sinner the love of God who reconciles. (CCC 1424) 

Penance requires . . . the sinner to endure all things willingly, be contrite of heart, confess with the lips, and practice complete humility and fruitful satisfaction. (CCC 1450) 

First, the penitent should act with a contrite heart. Contrition is “sorrow of the soul and detestation for the sin committed, together with the resolution not to sin again. When it arises from a love by which God is loved above all else, contrition is called “perfect” (i.e. the contrition of charity). Such contrition remits venial sins; it also obtains forgiveness of mortal sins if it includes the firm resolution to have recourse to sacramental confession as soon as possible. (CCC 1451-1452) 

Second act of a penitent is the confession of sins. Through such an admission, the penitent looks squarely at the sins he/she is guilty of, takes responsibility for them, and thereby opens him/herself again to God and to the communion of the Church in order to make a new future possible. (CCC 1455) 

The third act is a humble satisfaction. Many sins wrong our neighbor. One must do what is possible in order to repair the harm (e.g., return stolen goods, restore the reputation of someone slandered, pay compensation for injuries). But, sin also injures and weakens the sinner him/herself, as well as his/her relationships with God and neighbor. Absolution takes away sin, but it does not remedy all the disorders sin has caused. Raised up from sin, the sinner must still recover his full spiritual health by doing something more to make amends for the sin: he/she must “make satisfaction for” or “expiate” his/her sins. This satisfaction is also called penance. (CCC 1459) It can consist of prayer, an offering, works of mercy, service of neighbor, voluntary self-denial, sacrifices, and above all the patient acceptance of the cross we must bear. Such penances help configure us to Christ, who alone expiated our sins once for all. (CCC 1460) 

Reconciliation with God is thus the purpose and effect of this sacrament. For those who receive the sacrament of Penance with contrite heart and religious disposition, reconciliation is usually followed by peace and serenity of conscience with strong spiritual consolation. Indeed, the sacrament of Reconciliation with God brings about a true “spiritual resurrection,” restoration of the dignity and blessings of the life of the children of God, of which the most precious is friendship with God. (CCC 1468)