Roman Catechism 11.33

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

Section 33. Later on St. Basil wrote: Peter is made the foundation, because he says: Thou art Christ, the Son of the Living God; and hears in reply that he is a rock. But although a rock, he is not such a rock as Christ; for Christ is truly an immovable rock, but Peter, only by virtue of that rock. For Jesus bestows His dignities on others; He is a priest, and He makes priests; a rock, and He makes a rock; what belongs to Himself, He bestows on His servants.