But the Episcopal order is rightly judged to be in communion with Peter, as Christ commanded, if it be subject to and obeys Peter; otherwise it necessarily becomes a lawless and disorderly crowd. It is not sufficient for the due preservation of the unity of the faith that the head should merely have been charged with the office of superintendent, or should have been invested solely with a power of direction. But it is absolutely necessary that he should have received real and sovereign authority which the whole community is bound to obey. What had the Son of God in view when he promised the keys of the Kingdom of Heaven to Peter alone? Biblical usage and the unanimous teaching of the Fathers clearly show that supreme authority is designated in the passage by the word keys. Nor is it lawful to interpret in a different sense what was given to Peter alone, and what was given to the other Apostles conjointly with him. If the power of binding, loosening, and feeding confers upon each and every one of the Bishops the successors of the Apostles a real authority to rule the people committed to him, certainly the same power must have the same effect in his case to whom the duty of feeding the lambs and sheep has been assigned by God. "Christ constituted [Peter] not only pastor, but pastor of pastors; Peter therefore feeds the lambs and feeds the sheep, feeds the children and feeds the mothers, governs the subjects and rules the prelates, because the lambs and the sheep form the whole of the Church" (S. Bruonis Episcopi Signiensis Comment. in Joan., part iii., cap. 21, n. 55). Hence those remarkable expressions of the ancients concerning St. Peter, which most clearly set forth the fact that he was placed n the highest degree of dignity and authority. They frequently call him "the Prince of the College of the Disciples; the Prince of the holy Apostles; the leader of that choir; the mouthpiece of all the Apostles; the head of that family; the ruler of the whole world; the first of the Apostles; the safeguard of the Church." In this sense St. Bernard writes as follows to Pope Eugenius: "Who art thou? The great priest-the high priest. Thou art the Prince of Bishops and the heir of the Apostles.... Thou art he to whom the keys were given. There are, it is true, other gatekeepers of heaven and to pastors of flocks, but thou are so much the more glorious as thou hast inherited a different and more glorious name than all the rest. They have flocks consigned to them, one to each; to thee all the flocks are confided as one flock to one shepherd, and not alone the sheep, but the shepherds. You ask how I prove this? From the words of the Lord. To which - I do not say-of the Bishops, but even of the Apostles have all the sheep been so absolutely and unreservedly committed? If thou lovest me, Peter, feed my sheep. Which sheep? Of this or that country, or kingdom? My sheep, He says: to whom therefore is it not evident that he does not designate some, but all? We can make no exception where no distinction is made" (De Consideratione, lib. ii., cap. 8).
--Pope Leo XIII,
Satis Cognitum, On the Unity of the Church, 1896.
No one, therefore, unless in communion with Peter can share in his authority, since it is absurd to imagine that he who is outside can command in the Church.
They have not the heritage of Peter who have not the see of Peter, rent by their impious division.