Did not St. Irenaeus teach that all Churches must agree with the Roman Church? Why do the Orthodox not follow this precept from the early Church?
At the time, Rome was the capital of the empire, and this status led to everything else: Rome was where the great martyrs came to die, and the natural place of authority. The Roman Church was larger, more diverse, wealthier and more generous. In their struggle against all sorts of heretics who claimed ‘secret apostolic traditions,’ the defenders of orthodoxy could always point to the Faith of the Roman Church as a sure authority. Both Peter and Paul had preached there and together, they had entrusted the leadership of the Church to trustworthy men. Moreover, Christians from other apostolic Churches often went to Rome for business and as a result, the Faith was informed by a constant exchange of information. Irenaeus expressed this idea in these much-debated words:
Since, however, it would be very tedious, in such a volume as this, to reckon up the successions of all the Churches, we shall put to confusion all those who… assemble in unauthorized meetings; [we do this, I say,] by indicating that tradition derived from the Apostles, of the very great, the very ancient, and universally known Church founded and organized at Rome by the two most glorious Apostles, Peter and Paul; as also [by pointing out] the Faith preached to men, which comes down to our time by means of the successions of the bishops. For it is a matter of necessity that every Church should convene with this Church, on account of its preeminent authority, that is, the faithful everywhere, because the apostolic tradition has been preserved continuously by those [faithful men] who exist everywhere.
This passage is controversial because we only possess a Latin translation and there is always suspicion of tampering. Scholars also debate the original meaning and underlying Greek for convenire: is it to ‘go to,’ to ‘resort to’ or to ‘agree with?’ Either way, it seems rather futile to either minimize or exaggerate the strength of this passage because Irenaeus’ intention is rather straightforward. He is affirming the importance of assured apostolic Tradition at a time when heretics were introducing new doctrines that were totally at odds with the Faith preserved and taught in the Churches of apostolic origin. If Polycarp of Smyrna or Clement of Rome did not teach something, it is because they had not heard it from the Apostles. St. Irenaeus expresses this idea repeatedly, finding the truth is easy: one only has to see what the successors of the Apostles are teaching. In the West (Irenaeus is writing from Gaul, mainly for Westerners), the place to go is Rome. Rome has the most powerful apostolic foundation any Church can boast and it is known at this time for its faithfulness.
Therefore, at the very least then, Rome was a reliable witness to truth and one could conform to its teaching with assurance.
We must be careful not to make too much or too little of this text. Irenaeus does not say that Rome will always be faithful and he does not mention any special charisma or office held by the Bishop of Rome. However, he certainly considers Rome ‘first class’ but not ‘only in class.’
If Ignatius of Antioch was a witness to Rome’s primacy of love, Irenaeus focused on Rome’s primacy of witness to the apostolic Faith. It is understandable that the lost Greek original and its Latin translation have been the subject of much controversy. To summarize, convenire ad should probably be translated “resort to.” In this case, Irenaeus is saying that in order to ascertain controversial issues, the Churches should consult with the ‘apostolic witness’ par excellence, the Roman Church because the preaching of Peter and Paul was still fresh and preserved intact. This indeed became the practice of the Churches of East and West throughout the centuries. On the other hand, Irenaeus does not say that this is a perpetual charism of infallible authority inherent to the bishop of Rome, or that every Church must agree with Rome on everything. Regarding this last point, see Irenaeus’ intervention when Pope Victor attempted to alter the Paschal calendar of the Asiatic Churches.