18 It is common knowledge that among all the Scriptures, even those of the New Testament, the Gospels have a special preeminence, and rightly so, for they are the principal witness for the life and teaching of the incarnate Word, our savior. The Church has always and everywhere held and continues to hold that the four Gospels are of apostolic origin. For what the Apostles preached in fulfillment of the commission of Christ, afterwards they themselves and apostolic men, under the inspiration of the divine Spirit, handed on to us in writing: the foundation of faith, namely, the fourfold Gospel, according to Matthew, Mark, Luke and John.
Source: Dei Verbum (Vatican.va)