Another Letter of Clement of Alexandria Preserved in the East

Martin Hengel, Saint Peter: The Underestimated Apostle p. 147 "a puzzling Oriental tradition that appears in the writings of the scholarly Nestorian exegete Isho'dad of Merv (ninth century). In his introduction to the explanation of the Gospel of Mark, he writes: 

But as Clement gives testimony, Mark is a son of Peter. For Clement says in that extensive letter that he wrote against those who wanted to cast off marriage ties, in which he provides a list of those apostles who were married in the world, but who later became disciples of the Lord, that they preserved purity and holiness, as did Moses and others who, after they had been treated as worthy of receiving divine revelation, kept distant from marital relations and preserved holiness. For this one [Clement] says: "Or did they also reject the apostles? For Peter and Philip in- deed bore children; but Paul did not think it unfitting to greet his marriage partner in his letter; but he did not carry on with her because of the holiness of the service. 

Theodore Zahn supposes that Isho'dad cites an early writing, now lost, that only Clement himself mentions. Against this view, C. Heussi offers the objection that it could be a relatively free citation from Stromata, book 3 which deals with the topic of marriage and abstinence and which agrees quite closely in §§ 52-53 with the text from Isho'dad, except for the unique reference at the beginning of the citation that Clement identifies Mark as the physical son of Peter. Since this peculiar interpretation of 1 Pet. 5:13 does not appear anywhere else in the works of Clement, and since it more probably contradicts his information about the Second Gospel com- ing into existence in Rome, in which Mark appears as a "follower" of Peter, it is quite unlikely that the source of this information is Clement. Since, by contrast, it is just as unlikely that Isho'dad invented this himself, its source remains an open question. Whereas there is an easily understood consensus that 1 Pet. 5:13a — the fellow elect [suneklekte] in Babylon greet you" — refers to the Christian congregation in Rome, some earlier interpreters were of the opinion that this reference was to the wife of Peter. The most well-known advocate of such an interpretation was Albrecht Bengel in his Gnomon Novi Testamenti (on 1 Pet. 5:13): “Elected together with — Thus he appears to speak of his wife; cf. ch. iii. 7; for she was a sister, 1 Cor. ix. 5; and the mention of his son Mark agrees with this.” Thanks to Andrew Criddle for this reference to Martin Hengel.