Confession | Catholic Answers. This is a great article on the Sacrament of Reconciliation, courtesy of Catholic.com.
Are all of our sins—past, present, and future—forgiven once and for all when we become Christians? Not according to the Bible or the early Church Fathers. Scripture nowhere states that our future sins are forgiven; instead, it teaches us to pray, “And forgive us our debts, as we also have forgiven our debtors” (Matt. 6:12).
This sacrament is rooted in the mission God gave to Christ in his capacity as the Son of man on earth to go and forgive sins (cf. Matt. 9:6). Thus, the crowds who witnessed this new power “glorified God, who had given such authority to men” (Matt. 9:8; note the plural “men”). After his resurrection, Jesus passed on his mission to forgive sins to his ministers, telling them, “As the Father has sent me, even so I send you. . . . Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained” (John 20:21–23).