Apostolic Succession
Irenaeus
"For all these [heretics] are of much later date than are the bishops to whom the apostles handed over the churches, and this fact I pointed out most carefully in the third book. It is of necessity, then, that these aforementioned heretics, because they are blind to the truth, walk in devious paths, and on this account the vestiges of their doctrines are scattered about without agreement or connection. The path of those, however, who belong to the Church 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" (Ibid. 5:20:1).
Irenaeus
"Polycarp was instructed not only by the apostles and conversed with many who had seen Christ, but was also appointed bishop of the church in Smyrna by the apostles in Asia. I saw him in my early youth, for he tarried a long time and when quite old departed this life in a glorious and most noble martyrdom. He always taught those things which he learned from the apostles and which the Church had handed down and which are true. To these things the churches in Asia bear witness, as do also the successors of Polycarp even to the present time" (Ibid. 3:3:4).
Irenaeus
"It is necessary to obey those who are the presbyters in the Church, those who, as we have shown, have succession from the apostles, those who have received, with the succession of the episcopate, the sure charism of truth according to the good pleasure of the Father. But the rest, who have no part in the primitive succession [of bishops] and assemble wheresoever they will, must be held in suspicion....The true gnosis [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" (Ibid. 4:26:2, 33:8).