“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” -Against Heresies 1:10:2 [A.D. 189]

“[The Gnostic disciples of Marcus] have deluded many women. . . . Some of these women make a public confession, but others are ashamed to do this, and in silence, as if withdrawing from themselves the hope of the life of God, they either apostatize entirely or hesitate between the two courses” (Against Heresies 1:22 [A.D. 189]).

“Matthew also issued a written Gospel among the Hebrews in their own dialect, while Peter and Paul were preaching in Rome and laying the foundation of the Church.
Mark, the disciple and interpreter of Peter, did also hand down to us in writing what had been preached by Peter. Luke also, the companion of Paul, recorded in a book the Gospel preached by him.”
-Against Heresies, 3:1:1 [A.D. 189]

“It is possible, then, for everyone in every church, who may wish to know the truth, to contemplate the tradition of the apostles which has been made known to us throughout the whole world. And we are in a position to enumerate those who were instituted bishops by the apostles and their successors down to our own times, men who neither knew nor taught anything like what these heretics rave about.” (Against Heresies, 3:3:1).

“The successions of the 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. With that church, because of its superior origin, all the 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” -Against Heresies 3:3:2 [A.D. 189]

“The blessed apostles [Peter and Paul], having founded and built up the church [of Rome], they handed over the office of the episcopate to Linus. Paul makes mention of this Linus in the letter to Timothy [2 Tim. 4:21]. To him succeeded Anacletus, and after him, in the third place from the apostles, Clement was chosen for 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.”
-Against Heresies 3:3:3 [A.D. 189]

“In the time of Clement, no small dissension having arisen among the brethren in Corinth, the church in Rome sent a very strong letter to the Corinthians, exhorting them to peace and renewing their faith. . . . To this Clement, Evaristus succeeded . . . and now, in the twelfth place after the apostles, the lot of the episcopate [of Rome] has fallen to Eleutherius. 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” -Against Heresies 3:3:3 [A.D. 189]

“That is why it is surely necessary to avoid them [heretics], while cherishing with the utmost diligence the things pertaining to the Church, and to lay hold of the tradition of truth. . . . 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?” -Against Heresies, 3:4:1

“Eve… who was then still a virgin although she had Adam for a husband. having become disobedient, was made the cause of death for herself and for the whole human race; so also Mary, betrothed to a man but nevertheless still a virgin, being obedient, was made the cause of salvation for herself and for the whole human race.”
– Against Heresies 3:22:24
(Written in 189 A.D.)

“Thus, the knot of Eve’s disobedience was loosed by the obedience of Mary.
What the virgin Eve had bound in unbelief, the Virgin Mary loosed through faith.”
– Against Heresies 3:22:24

“He took bread, gave thanks, saying.
‘This is my body.’ The cup likewise, he confessed to be his blood. He taught the new sacrifice of the new covenant, of which the prophet Malachi signified beforehand… he makes it plain that the former people will cease to make offerings to God; but that, in every place, sacrifice will be offered to him, and indeed a pure one, for his name is glorified among the Gentiles.”
-Against Heresies 4:17:5

“For as the bread, which is produced from the earth, when it receives the invocation of God, is no longer common bread, but the Eucharist, consisting of two realities, earthly and heavenly; so also our bodies, when they receive the Eucharist, are no longer corruptible, having the hope of the resurrection to eternity.”
-Against Heresies, book 4:18:5

“[I]t is incumbent to obey the presbyters who are in the Church—those who, as I have shown, possess the succession from the apostles; those who, together with the succession of the episcopate, have received the infallible charism of truth, according to the good pleasure of the Father. But [it is also incumbent] to hold in suspicion others who depart from the primitive succession, and assemble themselves together in any place whatsoever, either as heretics of perverse minds, or as schismatics puffed up and self-pleasing, or again as hypocrites, acting thus for the sake of lucre and vainglory. For all these have fallen from the truth” -Against Heresies 4:26:2

“The true knowledge 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 succession the bishops have handed down the Church which is found everywhere” -Against Heresies 4:33:8

“If the Lord were from other than the Father, how could he rightly take bread, which is of the same creation as our own, and confess it to be his body and affirm that the mixture in the cup is his blood?”
-Against Heresies 4:33.2

“A Christian shall also
judge those who give rise to schisms.. . who look to their own advantage rather than the unity of the Church… For they can bring about no reformation of enough importance
to compensate for the evil arising
from their schism.”
-“Against Heresies” 4:33:7-8
(Written in 189 A.D.)

“The word ‘son’ has a two-fold meaning… whether as to respect to his being born so or by teaching of his doctrine.
For when any person has been taught from the mouth of another, he is termed the son of him whom instructs him, and the latter is called his father.”
– Against Heresies 4:41-42

“He has declared the cup, a part of creation, to be his own blood, from which he causes our blood to flow; and the bread, a part of creation, he has established as his own body, from which he gives increase unto our bodies.”
-Against Heresies 5:2:2

“When, therefore, the mixed cup [wine and water] and the baked bread receive the word of God and becomes the Eucharist, the body of Christ, and from these the substance of our flesh is increased and supported, how can they say that the flesh is not capable of receiving the gift of God, which is eternal life—flesh which is nourished by the body and blood of the Lord, and is in fact a member of him?”
-Against Heresies 5:2:2

“The Lord… was making a recapitulation of that disobedience that had occurred in connection with a tree, through the obedience that was upon a tree (the cross).
Furthermore, the original deception was to be done away with- the deception by which that virgin Eve was unhappily misled (by Satan).
That this was to be overturned was happily announced through means of the truth by the angel (Gabriel) to the Virgin Mary.”
– Against Heresies 5:19:1

“So if Eve disobeyed God, yet Mary was persuaded to be obedient to God.
In this way, the Virgin Mary might become the advocate of the virgin Eve.
And thus, as the human race fell into bondage to death by means of a virgin, so it is rescued by a virgin.
Virginal disobedience has been balanced in the opposite scale by virginal obedience.
For in the same way, the sin of the first created man received amendment by the correction of the First-Begotten.”
– Against Heresies 5:19:1

“All these heretics are of much later date than the Bishops to whom the Apostles handed over the Churches; this fact I pointed out most carefully in the third book. It is of necessity, then, that these heretics, because they are blind to truth, walk in various and devious paths; on this account the vestiges of their doctrine are scattered about without agreement or connection.
The path of those who belong to the Church, however, goes around the whole world; for it has the firm tradition of the Apostles, enabling us to see that the faith of all is one and the same.”
– Against Heresies 5:20:1

“‘And [Naaman] dipped himself . . . seven times in the Jordan’ [2 Kgs. 5:14]. It was not for nothing that Naaman of old, when suffering from leprosy, was purified upon his being baptized, but [this served] as an indication to us. For as we are lepers in sin, we are made clean, by means of the sacred water and the invocation of the Lord, from our old transgressions, being spiritually regenerated as newborn babes, even as the Lord has declared: ‘Except a man be born again through water and the Spirit, he shall not enter into the kingdom of heaven’” (Fragment 34 [A.D. 190]).

“Those same martyrs (the clergy in Lyons) commended Irenaeus, who was already at that time, a presbyter of Lyons, to the bishop of Rome, rendering abundant testimony to the man, as the following expressions show:
Once more and always we pray that you may rejoice in God, Pope Eleutherius.
This letter we have charged our brother and companion Irenaeus to convey to you, and we beg you to receive him as zealous for the covenant of Christ”
-Eusebius Quoting a Letter written in 175 A.D.
“Church History 5.4:1-2 Written in 312 A.D.)