Catechism of the Catholic Church §614 — excerpt
This sacrifice of Christ is unique; it completes and surpasses all other sacrifices. First, it is a gift from God the Father himself, for the Father handed his Son over to sinners in order to reconcile us with himself.
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.