Catechism of the Catholic Church §592 — excerpt
Jesus did not abolish the Law of Sinai, but rather fulfilled it (cf Mt 5:17-19) with such perfection (cf Jn 8:46) that he revealed its ultimate meaning (cf Mt 5:33) and redeemed the transgressions against it (cf Heb 9:15).
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.