St. Ephraem of Syria: "I have made thee a foundation of holy Church"

“SIMON, My disciple, I have made thee a foundation of holy Church, I called thee Rock on a previous occasion, because thou shalt be the support of all the buildings; thou art the overseer of those who will build My Church on earth. If they try to build anything evil, thou, the foundation, shalt reprimand them. Thou art the head of the fountain from which My doctrine shall be drunk, thou art the head of my disciples; I will give all people to drink through thee; yours is that life-giving sweetness I pour forth; I have chosen thee to be as it were the firstborn in My establishment and thou shalt become the heir of My treasures. The keys of My kingdom I have given thee. Lo, I have established thee prince over all My treasures.”

~St Ephraem of Syria: Sermons on Holy Week, 4, 1.

Christ Giving the Keys to St. Peter, Giovanni Battista Castello.
Illumination on vellum, 1598; Musée du Louvre, Paris.