Saint Quote: Pope Saint Callistus I

In this, then, we ought to be all of one mind, so that, according to apostolic teaching, we may all say the same thing, and that there be no divisions among us. Let us then be perfect in the same mind, and in the same judgment; in ready zeal for which work we congratulate ourselves on having your affection as our partner. For it is not meet for the members to be at variance with the head; but, according to the testimony of sacred Scripture, all the members should follow the head. It is matter of doubt, moreover, to no one, that the church of the apostles is the mother of all the churches, from whose ordinances it is not right that you should deviate to any extent. And as the Son of God came to do the Father's will, so shall ye fulfil the will of your mother, which is the Church, the head of which, as has been stated already, is the church of Rome. Wherefore, whatsoever may be done against the discipline of this church, without the decision of justice, cannot on any account be permitted to be held valid.

--Pope Saint Callistus I in his “First Epistle”