Catechism of the Catholic Church §123 — excerpt
Christians venerate the Old Testament as true Word of God. the Church has always vigorously opposed the idea of rejecting the Old Testament under the pretext that the New has rendered it void (Marcionism).
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.