The Sacrament of Penance and Reconciliation, more commonly known as Penance, Reconciliation, or Confession, is one of the seven sacraments of the Catholic Church. This is where the faithful obtain absolution for sins committed against God and neighbors. They are then reconciled with the community of the church.
It is by this sacrament that Christians are freed from sins committed after Baptism. The sacrament of Penance is considered the normal way to be absolved from mortal sin–something that would otherwise condemn one to Hell.
The scriptural basis for this sacrament is taken from John 20:23 where Jesus breathed the Holy Spirit into the Apostles saying “Whose sins you shall forgive, they are forgiven them; and whose sins you shall retain, they are retained.”
Another basis for this sacrament is taken from James 5:16 “Confess therefore your sins one to another: an pray one for another, that you may be saved.”
The sacrament has four elements to it. Three on the part of the penitent: contrition, confession, and satisfaction. One on the part of the minister of the sacrament: absolution.
Catholics oft distinguish between two types of sin: mortal and venial.
Mortal sins are a “most grave violation of God’s law” that “turns man away from God”. Someone who is aware of having committed mortal sins must repent of having done so and must confess them in order to benefit from the sacrament.
Venial sins are the kind that “do not set us in direct opposition to the will and friendship of God” can be remitted by contrition and reception of other sacraments. Every sin involves “an unhealthy attachment to creatures”, purification from which is called the temporal punishment for sin (as opposed to the eternal punishment merited by mortal sin). The satisfaction required of the penitent is not an essential part of the sacrament, because the primary effect of remission of guilt and eternal punishment is obtained without it; but it is an integral part, because it is required for obtaining the secondary effect of this purification or remission of temporal punishment.
A major penitentiary, Cardinal James Stafford, said that “we are saved by faith and the sacraments of faith”. According to Catholic theology, the sacrament of Penance is the only ordinary way for the forgiveness of mortal sins committed after Baptism. Nevertheless, mortal sins are already forgiven by contrition (not attrition, hence also called perfect contrition), as the Church teaches. The difference between perfect contrition and attrition is that the former is grounded in charity and filial fear while attrition is grounded in fear only.
A customary prayer in invoked that is equivalent to an act of contrition. Contrition by necessity includes the desire for receiving the sacrament of Penance, that is the (at least implicit) will to subject one’s sins to the sacrament instituted as ordinary way of forgiveness, because one cannot on the one hand love God above all for His goodness He has in himself and desire His forgiveness, and on the other hand reject the ordinary means of the said forgiveness. In a sacramental sense, it may perhaps be said that it is by this way that the effect of forgiveness and re-bestowment of grace through works.
A Catholic is normally required to receive the sacrament of Penance at least once a year. It is normal to refrain from holy Communion until undergoing a confession as one has not returned to a state of grace.