When he celebrates the sacrament of Reconciliation, or Penance, the priest is fulfilling the ministry of the Good Shepherd who seeks the lost sheep and of the Father who welcomes home the prodigal son on his return. The priest is the sign and the instrument of God’s merciful love for the sinner.
“The whole power of the sacrament of Penance consists in restoring us to God’s grace and joining us with him in an intimate friendship.” 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.
This sacrament reconciles us with the Church. Sin damages or even breaks fraternal communion. The sacrament of Penance repairs or restores it. In this sense it does not simply heal the one restored to ecclesial communion, but has also a revitalizing effect on the life of the Church which suffered from the sin of one of her members. Re-established or strengthened in the communion of saints, the sinner is made stronger by the exchange of spiritual goods among all the living members of the Body of Christ, whether still on pilgrimage or already in the heavenly homeland.
(Catechism of the Catholic Church, paragraphs 1468-1469)