It is called the sacrament of forgiveness, since by the priest’s Sacramental absolution, God grants the penitent “pardon and peace.”
The sacrament of Reconciliation imparts to the sinner the life of God who reconciles: “Be reconciled to God.” He who lives by God’s merciful love is ready to respond to the Lord’s call: “Go; first be reconciled to your brother.”
Catechism of the Catholic Church, Article 4, I