Chapter 11 — Part I: The Creed — Article IX: The Holy Catholic Church; the Communion of Saints
Section 41. Moreover, the Church alone has the legitimate worship of sacrifice, and the salutary use of the Sacraments, which are the efficacious instruments of divine grace, used by God to produce true holiness. Hence, to possess true holiness, we must belong to this Church. The Church therefore it is clear, is holy, and holy because she is the body of Christ, by whom she is sanctified, and in whose blood she is washed.