Where the bishop is present, there is the Catholic Church

Being come together in the same place, let there be one prayer, one supplication, one mind, one hope, in love and in joy undefiled. There is one Jesus Christ, than Whom nothing is more excellent. Therefore all should run together as into one temple of God, as to one altar, as to one Jesus Christ, who came forth from the Father, and is with and has gone to one.

In like manner, everyone who has received from God the power of distinguishing and yet follows an unskillful pastor and receives a false opinion for the truth shall be punished ... Be not deceived: if any man follows him who separates from the truth, he shall not inherit the kingdom of God; and if any man does not stand aloof from the preacher of falsehood he shall be condemned to Hell.

For some are in the habit of carrying about the name in wicked guile, while they still practice things unworthy of God. You must flee these as you would wild beasts. For they are ravening dogs, who bite secretly, against whom you must be on your guard, since they are men who can scarcely be cured.

Be obedient to the bishop and to one another, as Jesus Christ was in the flesh to the Father, and the apostles to Christ and to the Father and to the Spirit, so that there may be unity in flesh and in spirit.

Wherever the bishop shall appear, let the multitude of also be, just as wherever Jesus Christ is, there is the catholic [i.e., universal] church. It is not lawful either to baptize or to celebrate a love feast without the bishop, but whatever he approves of, that is also pleasing to God.

Therefore run together as into one temple of God, as to one altar, as to one Jesus Christ, who came forth from one Father, and is with and has gone to one.