Catechism of the Catholic Church §613 — excerpt
Christ's death is both the Paschal sacrifice that accomplishes the definitive redemption of men, through "the Lamb of God, who takes away the sin of the world", and the sacrifice of the New Covenant, which restores man to communion with God by reconciling him to…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.