Ireneaeus, Against Heresies:AD 180
"For the Church, although dispersed throughout the whole world even to the ends of the earth, has received from the Apostles and from their disciples the faith in one God, Father Almighty, Creator of heaven and earth and seal and all that is in them...
As I said before, the Church, having received this preaching and this faith, although she is disseminated throughout the whole world, yet guarded it, as if she occupied but one house. She likewise believes these things just as if she had but one soul and one and the same heart; and harmoniously she proclaims them and teaches them and hands them down, as if she possessed but one mouth. For, while the languages of the world are diverse, nevertheless, the authority of the tradition is one and the same.
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Nor will any of the rulers of the Churches, whatever his power of eloquence, teach otherwise, for no one is above the teacher; nor will he who is weak in speaking detract from the tradition. for the faith is one and the same, and cannot be amplified by one who is able to say much about it, nor can it be diminished by one who can say but little.
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Creation itself revals Him that created it; and the work made is itself suggestive of Him that made it; and the world manifests Him that arranged it. Every Church throughout the whole world has received this tradition from the Apostles.
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It is possible, then, for everyone in every Church, who may wish to know the truth, to cotemplate the tradition of the Apostles which has been made known thoughout the whole world. And we are in a position to enumerate those who were instituted bishops by the Apostles, and their successors to our own times: men who neither knew nor taught anything like these heretics rave about. For if the Apostles had known hidden mysteries which they taught to the elite secretly and apart from the rest, they would have handed them down especially to the ones to whom they were committing the self-same Churches. For surely they wished all those and their successors to be perfect and without reproach, to whim they handed on their authority.
But since it would be too long to enumerate in such a volume as this the successions of all the Churches, we shall confound all those who, in whatever manner, whether through self-satisfaction or vainglory, or though blindness and wicked opinion, assemble other than where it is proper, by pointing out here the successions of bishops of the greatest and most ancient Church known to all, founded and organized at Rome by the two most glorious Apostles, Peter and Paul, that Church which has the tradition and the faith which comes down to us after having been announced to men by the Apostles. For with this Church, because of its superior origin, all Churches must agree, that is, all the faithful in the whole world; and it is in her that the faithful everywhere have maintained the Apostolic tradition.
...Clement was chosen to the episcopate. He had seen the blessed Apostles and was acquainted with them. It might be said that he still heard the echoes of the preaching of the Apostles, and had their traditions before his eyes...In this order, and by the teaching of the Apostles handed down in the Church, the preaching of the truth has come down to us.
...[Polycarp] always taught those things which he had learned from the Apostles, and which the Church had handed down, and which are true. To these things all the Churches in Asia bear witness, as do also the successors to Polcarp even to the present time.
...When, therefore, we have such proofs, it is not necessary to seek among others the truth which is easily obtained by the Church. For the Apostles, like a rich man in a band, deposited with her most copiously everything which pertains to the truth; and everyone whosoever wishes draws from her the drink of life. For she is the entrance to life, while all the rest are thieves and robbers. That is why it is surely necessary to avoid them, while cherishing with utmost diligence the things pertaining to the Church, and to lay hold of the tradition of truth. What then? If there should be a dispute over some kind of question, ought we not have recourse to the most ancient Churches in which the Apostles were familiar, and draw from them what is clear and certain in regard to that question? [NB: NOTE NO MENTION OF SCRIPTURE HERE, BUT THE AUTHORITY OF THE CHURCH]? What if the Apostles had not in fact left writings to us? Would it not be necessary to follow the order of tradition, which was handed down to those to whom they entrusted the Churches?
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The true gnosis is the doctrine of the Apostles, and the ancient organization of the Church throughout the whole world, and the manifestation of the body of Christ according to the succession of bishops, by which successions the bishops have handed down the Church which is found everywhere; and the very complete tradition of the Scriptures, which have come down to us by being guarded against falsification, and which are received without addition or deletion; and reading without falsification, and a legitimate and diligent exposition according to the Scriptures, without danger and without blasphemy; and the pre-eminent gift of love, which is more precious that knowledge, more glorious than prophecy, and more honored than all the other charismatic gifts."
It is interesting to note that Irenaeus wrote at a time when the canon was under significant discussion due to the gnostics. He is among the first to offer the fourfold Gospel as authoritative, eschewing the Gospel of Thomas and other gnostic works (see Elaine Pagels, "The Gnostic Gospels" and "Beyond Belief"). He does so because theseGospels correspond with what the Apostles handed to their successors, who were the guardians for the Church of the full deposit of faith.
Irenaeus speaks of "one heart," one voice, etc. Scripture did not come about outside of the process of the Church's compiling it and preserving it from corruption, and it is because the Church did so that the NT as we know it came about. Scripture was the first fruit of the Apostolic Tradition manifest in the Church. Irenaeus sees a unity in the Church, not an amalgamation of local independent communities, the ties of which were the Bishops who succeeded the Apostles and brought forward their teachings, some of which were written down.
Questions that arose were to be referred to the Ancient Churches , not to the writings.
The Church, then, not just Scripture, not just oral Tradition, but the Church, is the guardian of the fullness of what Christ revealed to the Apostles.