CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 122–125

122 Indeed, "the economy of the Old Testament was deliberately so oriented that it should prepare for and declare in prophecy the coming of Christ, redeemer of all men." "Even though they contain matters imperfect and provisional," the books of the Old Testament bear witness to the whole divine pedagogy of God's saving love: these writings "are a storehouse of sublime teaching on God and of sound wisdom on human life, as well as a wonderful treasury of prayers; in them, too, the mystery of our salvation is present in a hidden way."
123 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).
124 "The Word of God, which is the power of God for salvation to everyone who has faith, is set forth and displays its power in a most wonderful way in the writings of the New Testament" which hand on the ultimate truth of God's Revelation. Their central object is Jesus Christ, God's incarnate Son: his acts, teachings, Passion and glorification, and his Church's beginnings under the Spirit's guidance.
125 The Gospels are the heart of all the Scriptures "because they are our principal source for the life and teaching of the Incarnate Word, our Savior".