The Sacrament of Reconciliation (Confession, Penance) is the means and the sign that Christ gave us to show His willingness to heal us when, through our own human frailty, we turn in on ourselves and away from Him and our neighbor.
This is the sign God has given us that through the words of His priest ("I now absolve you from your sins") whatever harm we have done to our relationship with our God is healed and we are restored to a state of warm friendship with our Father in heaven.
Catholics believe that all of the sacraments were instituted by Jesus Christ himself. In the case of Confession, that institution occurred on Easter Sunday when Christ first appeared to the apostles after his Resurrection.
Breathing on them, he said: “Receive the Holy Spirit. For those whose sins you forgive, they are forgiven; for those whose sins you retain, they are retained” (John 20:22-23).
What Is Required?
Three things are required of a penitent in order to receive the sacrament worthily: The penitent must be contrite—or, in other words, sorry for their sins. They must confess those sins fully, in kind and in number. They must be willing to do penance and make amends for his sins .