There is no version of First and Second Timothy, Titus, and Hebrews in his scripture at all, and even the epistles that are there have been mutilated, since they are not all there but are counterfeits. I have made this laborious, searching compilation from the scripture he has chosen, Paul and the Gospel according to Luke, so that all who are attempting to contradict his imposture may understand that the altered sayings have been fraudulently inserted, and that any not in their proper places have been stolen from them by his audacity. For the oaf thought that only these run counter to his false notion. But there is a third work of my scholarship: the compilation of whatever material he and we have in common, and whose meaning is the Saviour's incarnation and his testimony to the agreement of the New Testament with the Old—and the acknowledgment in the Gospel, by the Son of God, that God is the maker of heaven and earth and the same God who spoke in the Law and the prophets, and that this God is his own Father. And here is the brief arrangement of that work of mine, transcribed word for word by myself from copies of Marcion in the form of scholia with exegetical comments, to serve as an outline.
Now let us stop right there and take note that while many other sources tell us that the Marcionites rejected the Acts of the Apostles and the Pastoral Epistles, no one ever explicitly says that they rejected the Epistle to the Hebrews. As Rothschild notes, it is an argument from silence in Tertullian (i.e. Tertullian's silence regarding Hebrews).
Before we tackle Epiphanius claim to have actually held a Marcionite canon, let us remind ourselves that not only is the fourth century Father our only source for the Marcionite canon beginning with Galatians but now he is our only source to boldly declare that the Epistle to the Hebrews was also 'removed' from their canon. Without Epiphanius there would be only arguments from silence in Tertullian. Yet let's stop right there and note that if - as I have suggested - Irenaeus's Against Marcion was the ultimate source for both Tertullian and Epiphanius, the silence about Hebrews is immediately explained insofar as Irenaeus strangely never cites from Hebrews.
Now let's return to Epiphanius's claim to have had copies of the Marcionite scriptures in his possession. Bart Ehrman deals with a parallel argument in the Panarion and comes to much the same conclusion as I am suggesting - i.e. Epiphanius is a liar. We read in Ehrman's latest book Forgery and Counterforgery (which I am reading and happen to love):
Epiphanius, as we have seen, does claim to have read the Phibionites' literature, and this claim is sometimes taken to substantiate his account, even though he himself both provides the account and makes the claim. Here as always Epiphanius must be taken with a pound of salt. The books of the Phibionites could not have been widely circulated outside the group—at least any books that documented their scandalous activities. So possibly Epiphanius read some of their theological or mythological treatises, and drew (or conjured up) his own conclusions. But did he read the Greater Questions of Mary and quote it accurately in his Panarion? There is evidence that some such book did at one time exist: it is at least mentioned elsewhere, although there is no evidence that any other author of a surviving work actually had seen it.32 But nowhere else, outside of Epiphanius, are we given any indication of its contents. The episode that Epiphanius cites of Jesus engaging in illicit sex, coitus interruptus, and consumption of his own semen coincides perfectly well with Epiphanius' description of the activities of the Phibionites themselves. Moreover, Epiphanius almost certainly fabricated the accounts of these activities: he had never seen them, no one from within the group would have told him about them, they could not have been described in their other literature, and they stand at odds with what we do know of the ethical impulses of all other Gnostic groups from antiquity. On these grounds I would propose that Epiphanius made up the account of the Greater Questions of Mary. The Phibionites may have had a long-lived reputation for scurrilous activities— thus Gero —but if they were like every other Gnostic group for which we have firsthand knowledge—and why would they not be?—then their antimaterialist theology did not lead to socially scandalous and illegal promiscuity, but to ascetic dismissal of the passions of the flesh. The conclusion seems inevitable: Epiphanius got the matter precisely wrong and then fabricated his accounts, and at least one document, in order to make his point. [p. 23, 24]
Ehrman's account is bang on and only says what Plooij and others have already noted - Epiphanius is a completely unreliable source.
