You have written on my account the Church now has a portion of itself in a state of dispersion. In truth, the whole people of the Church are collected together and made one and joined to each other in an indivisible harmony. They alone have remained outside who, were they within, would have to be ejected...And the Lord too, in the Gospel, when the disciples abandoned Him while He was speaking, turned to the twelve and said, "and do you too wish to go away?" Peter answered Him, saying, "Lord, to whom shall we go? You have the word of eternal life; and we believe and know that you are the Son of the Living God."
There speaks Peter, upon whom the Church would be built, teaching in the name of the Church and showing that even if a stubborn and proud multitude withdraws because it does not wish to obey, yet the Church does not withdraw from Christ. The people joined to the priest and the flock clinging to their shephers are the Church.
You ought to know, then, that the bishop is in the Church and the Church in the bishop; and if someone is not with the bishop, he is not in the Church. They vainly flatter themselves who creep up, not having peace with the priests of God, believing they are secretly in communion with certain individuals. For the Church, which is One and Catholic, is not split or divided, but it is indeed united and joined by the cement of priests who adhere to one another.