Two generations pass and the aged S. Ignatius, on his way to martyrdom, attests the same fact. "Where is Jesus Christ," he says, "there is the Catholic Church." The King is in His Kingdom; the Master in His House; the Lord in His Temple. The bishops throughout the world inseparably linked together are His mind: and the presidency of charity, which is the inner life of all this spiritual empire, is at Rome. S. Ignatius and the author of the letter to Diognetus write just after the expiration of the apostolic period; and they both regard Christians as one mass throughout the world, living under a divine form of spiritual government. No one who studies their words can doubt that the one Body and the one Spirit were as visible to their eyes and as dear to their heart as to S. Paul.
We pass two generations further and S. Irenæus repeats the same testimony. The interval has been filled by incessant attacks of heresies, and the Bishop of Lyons dwells upon the fact that the Church speaks with one voice through all the regions of the earth as being one House of God, and that the seat of this its unity is in the great See founded by the Princes of the Apostles at Rome. He reproduces at great length the statements of S. Paul that the safeguard of truth lies in the one apostolic ministry, for which he runs up to the fountain-head in Rome. It is in the living voice and the teaching office of the Church that he sees a perpetual preservative against whatever error may arise. Thus it has been up to his time, and thus it will ever be.
Another period of seventy years runs on, and we come to the just-cited testimony of Cyprian, who therefore said nothing new, nor anything exaggerated; but when the truth was assailed in its very citadel, he spoke out and described wherein its strength lay. He gathers up and gives expression to the two hundred and twenty years between the day of Pentecost and his own time. Here are the creative words of our Apostle and High-priest explained and attested and exhibited as having passed into fact by four witnesses, first S. Paul, then S. Ignatius, thirdly S. Irenæus, fourthly S. Cyprian. Between all the five there is no shadow of divergence, between the Master who designed the building and the servants who described its erection; between the Prophet who foretold and the historians who recorded. The one said, Upon this rock I will build my Church; the others pointed out that the work was accomplished.