“Our Lord Jesus Christ . . . has placed the principal charge on the blessed Peter, chief of all the apostles, and from him as from the head wishes his gifts to flow to all the body, so that anyone who dares to secede from Peter’s solid rock may understand that he has no part or lot in the divine mystery. He wished him who had been received into partnership in his undivided unity to be named what he himself was, when he said: ‘You are Peter, and upon this rock I will build my Church’ [Matt. 16:18], that the building of the eternal temple might rest on Peter’s solid rock, strengthening his Church so surely that neither could human rashness assail it nor the gates of hell prevail against it” (Letters 10:1 [A.D. 445).
"Our Lord Jesus Christ . . . established the worship belonging to the divine [Christian] religion. . . . But the Lord desired that the sacrament of this gift should pertain to all the apostles in such a way that it might be found principally in the most blessed Peter, the highest of all the apostles. And he wanted his gifts to flow into the entire body from Peter himself, as if from the head, in such a way that anyone who had dared to separate himself from the solidarity of Peter would realize that he was himself no longer a sharer in the divine mystery” (ibid., 10:2–3).
“Although bishops have a common dignity, they are not all of the same rank. Even among the most blessed apostles, though they were alike in honor, there was a certain distinction of power. All were equal in being chosen, but it was given to one to be preeminent over the others. . . . [So today through the bishops] the care of the universal Church would converge in the one See of Peter, and nothing should ever be at odds with this head” (ibid., 14:11).