Mortal Sin and the Sacrament of Confession: The Catholic Church teaches that mortal sin is a grave offense against God's law that destroys the life of grace in the soul. Mortal sin involves serious matter, full knowledge, and deliberate consent. When committed, it ruptures the individual's relationship with God and the Church. The Catechism of the Catholic Church describes mortal sin as a turning away from God, a rejection of His love, and a choice of finite goods over the infinite good of God. Mortal sin leads to spiritual death and eternal separation from God if not repented and forgiven.
Regarding the sacrament of confession, the Catholic Church teaches that it is the ordinary means established by Christ for the forgiveness of sins committed after baptism. Through confession, the penitent confesses their sins to a priest, who acts in persona Christi ("in the person of Christ"), and receives absolution, the forgiveness of sins, through the power of God's grace. The Catechism teaches that confession reconciles the penitent with God and the Church, restores sanctifying grace, and strengthens the individual against future sin.