Roman Catechism 11.52

Chapter 11 — Part I: The Creed — Article IX: The Holy Catholic Church; the Communion of Saints

Section 52. Since, therefore, this Article, no less than the others, is placed above the reach, and defies the strength of the human understanding, most justly do we confess that we know not from human reason, but contemplate with the eyes of faith the origin, offices and dignity of the Church.