Come now, you who would indulge a better curiosity, if you would apply it to the business of your salvation, run over the apostolic churches, in which the very thrones of the apostles are still pre-eminent in their places, in which their own authentic writings are read, uttering the voice and representing the face of each of them severally. Achaia is very near you, (in which) you find Corinth. Since you are not far from Macedonia, you have Philippi; (and there too) you have the Thessalonians. Since you are able to cross to Asia, you get Ephesus. Since, moreover, you are close upon Italy, you have Rome, from which there comes even into our own hands the very authority (of apostles themselves). How happy is its church, on which apostles poured forth all their doctrine along with their blood! where Peter endures a passion like his Lord’s! where Paul wins his crown in a death like John’s where the Apostle John was first plunged, unhurt, into boiling oil, and thence remitted to his island-exile! See what she has learned, what taught, what fellowship has had with even (our) churches in Africa! One Lord God does she acknowledge, the Creator of the universe, and Christ Jesus (born) of the Virgin Mary, the Son of God the Creator; and the Resurrection of the flesh; the law and the prophets she unites in one volume with the writings of evangelists and apostles, from which she drinks in her faith. This she seals with the water (of baptism), arrays with the Holy Ghost, feeds with the Eucharist, cheers with martyrdom, and against such a discipline thus (maintained) she admits no gainsayer.
Tertullian
Against Marcion
The Prescription Against Heretics
Chapter XXXVI