The Trouble with Sources - Never Salute a Marcionite

The Church Fathers, an 11th-century
Kievan miniature from Svyatoslav's 

There are three primary sources for the specific content and text of the Marcionite New Testament, Tertullian's Adversus Marcionem, Epiphanius' Panarion book 42, and the first two parts of Dialogue Adamantius. Each has their own problems. Tertullian's use of paraphrase and reference to the Catholic text at times with out notice. Epiphanius is writing much later than the others, and his source text shows signs of having been adjusted here and there toward the Catholic text in the interim.

Yet it is Dialogue Adamantius which is the most difficult. John Clabeaux states (page 12, A Lost Edition of the Letters of Paul),

'The Dial. Adam. is clearly artificial (Adamantius Dialogue xv). There are two claims by the title character (1.5 and 5.22) that he used a Marcionite Apostolikon. These claims, in light of the research of this study, are untenable. The author's claims, even if they are taken seriously, contain two major limitations: They do not speak for every Pauline citation in Dial. Adam.; and (2) when Adamantius says "ἐκ τοῦ αὐτῶν ἀποστολικοῦ" (5.22), he may merely be referring to those letters of Paul which the Marcionites accepted, without implying a reference to the text that is in fact used (catholic or Marcionite).'