Our LORD Jesus Christ, Saviour of mankind, instituted the observance of the Divine religion which He wished by the grace of GOD to shed its brightness upon all nations and all peoples in such a way that the Truth, which before was confined to the announcements of the Law and the Prophets, might through the Apostles' trumpet blast go out for the salvation of all men(5), as it is written: "Their sound has gone out into every land, and their words into the ends of the world(6)." But this mysterious function(7) the LORD wished to be indeed the concern of all the apostles, but in such a way that He has placed the principal charge on the blessed Peter, chief of all the Apostles(8): and from him as from the Head wishes His gifts to flow to all the body: so that any one who dares to secede from Peter's solid rock may understand that he has no part or lot in the divine mystery. For He wished him who had been received into partnership in His undivided unity to be named what He Himself was, when He said: "Thou art Peter, and upon this rock I will build My Church(9) :" that the building of the eternal temple by the wondrous gift of GOD'S grace 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. But this most holy firmness of the rock, reared, as we have said, by the building hand of GOD, a man must wish to destroy in over-weaning wickedness when he tries to break down its power, by favouring his own desires, and not following what he received from men of old: for he believes himself subject to no law, and held in check by no rules of GOD's ordinances and breaks away, in his eagerness for novelty, from your use and ours, by adopting illegal practices, and letting what he ought to keep fall into abeyance.The solidarity of the Church built upon the rack of S. Peter must be everywhere maintained.
Source of St. Leo the Great's writings
H/T to Insight Scoop: St. Leo the Great: Champion of Christological faith, messenger of peace and love