Now of Serapion's exercise in letters it is likely that other memoirs too are preserved among others, but to us there have come down only those addressed to Domninus, who in the time of the persecution had fallen away from the faith in Christ to the Jewish will-worship; and those to Pontius and Caricus, men of the church; and other letters to yet others.
And there is another treatise composed by him concerning the so-called Gospel according to Peter, which he made in refutation of the things falsely said in it, on account of certain persons in the community at Rhossus who, under pretext of the said writing, had veered off into heterodox teachings. From this it is reasonable to set down a few brief words, by which he sets forth the opinion he held concerning the book, writing thus:
「For we, brethren, receive both Peter and the other apostles as Christ; but the writings that go falsely under their names we, as men of experience, reject, knowing that such things we did not receive by tradition.」
「For when I was with you I supposed that you all held fast to the right faith; and, not having gone through the Gospel put forward by them under the name of Peter, I said that, if this is the only thing that seems to cause you pettiness of spirit, let it be read. But now, having learned from what was told me that their mind lay lurking in some heresy, I will be zealous to come to you again; so that, brethren, expect me shortly.」
「But you, brethren, having grasped of what heresy Marcianus was, and how he even contradicted himself, not understanding what he was saying, will learn from the things written to you.」
「For we were able to obtain this very Gospel from others who had practised it—that is, from the successors of those who had begun it, whom we call Docetae (for the greater part of the opinions are of their teaching)—and, using their copy, to go through it and find the greater part to belong to the right word of the Saviour, but some things to be additions set apart, which we have also subjoined for you.」 And these are the words of Serapion.