No, that wasn't from St. Irenaeus, it was an excerpt of what I had previously posted from the Tome of Pope St. Agatho to the Third Synod of Constantinople. As I noted, the Council wrote back to St. Agatho:
Therefore to thee, as to the bishop of the first see of the Universal Church, we leave what must be done, since you willingly take for your standing ground the firm rock of the faith, as we know from having read your true confession in the letter sent by your fatherly beatitude to the most pious emperor: and we acknowledge that this letter was divinely written as by the Chief of the Apostles, and through it we have cast out the heretical sect of many errors which had recently sprung up, having been urged to making a decree by Constantine who divinely reigns, and wields a most clement sceptre.
To the Emperor, the Council declared (in the Prosphoneticus):
Thereafter being inspired by the Holy Ghost, and all agreeing and consenting together, and giving our approval to the doctrinal letter of our most blessed and exalted pope, Agatho, which he sent to your mightiness, as also agreeing to the suggestion of the holy synod of one hundred and twenty-five fathers held under him, we teach that one of the Holy Trinity, our Lord Jesus Christ, was incarnate, and must be celebrated in two perfect natures without division and without confusion. ... But the highest prince of the Apostles fought with us: for we had on our side his imitator and the successor in his see, who also had set forth in his letter the mystery of the divine word. For the ancient city of Rome handed thee a confession of divine character, and a chart from the sunsetting raised up the day of dogmas, and made the darkness manifest, and Peter spoke through Agatho, and thou, O autocratic King, according to the divine decree, with the Omnipotent Sharer of thy throne, didst judge.
From all this it is undeniable that St. Agatho's letter (the Roman Church "remains undefiled unto the end, according to the divine promise of the Lord and Saviour himself") was approved by the Council and belongs to its own teaching, and while St. Irenaeus was not infallible, I think we can both agree that III Constantinople was. And the promise referred to is not Mt. 16:18, but Lk. 22:32, as you will see if you consult the longer excerpts of the letter I gave in my post 19 on this thread.
Trying to pick a fight with another denomination are we?
The one, holy, catholic, and apostolic Church is not a "denomination".
I stand coprected. But "...and we acknowledge that this letter was divinely written as by the Chief of the Apostles..."
They were being duly respectful and had no desire to pick a fight with the Primus inter Pares.
Well, if the reference is to Lk. 22:32, that prayer is fulfilled in all of St. Peter's successors, but not in all of the sees he established or helped establish because, as history points out, some went one way and somewent another.
"The one, holy, catholic, and apostolic Church is not a 'denomination'." No, but the Old Catholic Church of Utrecht is a denomination, just as is yours, and it's not the OHCAC any more than your denomination is.