Irenaeus of Lyons, Against Heresies 3.3.4
Polycarp was not only taught by the apostles and conversed with many who had seen our Lord, but was also appointed bishop of the church in Smyrna by the apostles in Asia. We ourselves saw him in our early years; he persevered a long time and, as a very old man, departed this life after gloriously and most nobly suffering martyrdom. He always taught the things he had learned from the apostles, which the church also handed down, and these alone are true.
All the churches in Asia bear witness to these things, as do those who have succeeded Polycarp to this day. He is a man of far greater authority and a more faithful witness to the truth than Valentinus, Marcion, and the rest who hold perverse opinions. For when he came to Rome under Anicetus, he converted many of the heretics mentioned earlier to the Church of God, proclaiming the one and only truth that he had received from the apostles and handed down to the church.
There are those who heard that when John the Lord's disciple went to bathe in Ephesus and saw Cerinthus inside, he rushed out of the bathhouse unwashed, declaring that he feared the building would collapse with Cerinthus, the enemy of truth, inside. Polycarp himself, when Marcion once met him and asked, 'Do you recognize us?' replied, 'I recognize you as the firstborn of Satan.'
The apostles and their disciples took such care to avoid even verbal communion with anyone who had corrupted the truth, just as Paul says: 'Avoid a heretical person after one correction, knowing that such a person is perverse and stands self-condemned.' There is also a letter of Polycarp to the Philippians, written most perfectly, from which those who desire and care for their salvation can learn the character of his faith and the preaching of the truth.
Moreover, the church in Ephesus, founded by Paul and enduring with John until the times of Trajan, stands as a true witness to the tradition of the apostles.
Latin
Et Polycarpus autem non solum ab Apostolis edoctus, et conversatus cum multis ex eis qui Dominum nostrum viderunt ; sed etiam ab Apostolis in Asia, in ea que est Smyrnis Ecclesia constitutus Episcopus, quem et nos vidimus in prima nostra eetate, multum enim perseveravit, et valde senex gloriosissime et nobilissime martyrium faciens exivit de hac vita, heee docuit semper quie ab Apostolis didicerat, quee et Ecclesiz tradidit, et sola sunt vera. estimonium his perhibent que sunt in Asia ecclesi omnes, et qui usque adhuc successerunt Polycarpo: qui vir multo majoris auctoritatis, et fidelior veritatis est testis, quam Valentinus et Marcion, et reliqui qui sunt perversze sententiz. Is enim est qui sub Aniceto cum advenisset in urbem, multos ex his quos preediximus, hzereticos convertit in Ecclesiam Dei, unam et solam hane veritatem annuntians ab Apostolis percepisse se, quam et Keclesize tradidit. Et sunt qui audierunt eum®, quoniam Johannes Domini discipulus in Epheso iens lavari, cum vidisset intus Cerinthum, exsilierit de balneo non lotus, dicens, quod timeat ne balneum concidat, cum intus esset Cerinthus inimicus veritatis. Et ipse autem Polycarpus Marcioni aliquando occurrenti sibi, et dicenti, Cognoscis nos? respondit: Cognosco te primogenitum Satan. Tantum Apostoli et horum discipuli habuerunt timorem, Sut neque verbo tenus communicarent alicui eorum qui adulteraverant veritatem, quemadmodum et Paulus ait: Hareticum autem hominem post unam correptionem devita, sciens quoniam perversus est qui est talis, et est a semetipso damnatus, Est autem et epistola Polycarpi ad Philippenses scripta perfectissima, ex qua et characterem fidei ejus, et preedicationem veritatis, qui volunt et curam habent suz salutis, possunt discere. Sed et que est Ephesi ecclesia a Paulo quidem fundata, Johanne autem permanente apud eos usque ad Trajani tempora, testis est verus Apostolorum traditionis,