Now to continue with my demonstration from last night before I got too tired to continue, I think it is extremely unusual that Tertullian acknowledges that the Marcionites acknowledge Marcion not Paul was responsible for their understanding about the separation of the Law and the Gospel. Again, Tertullian begins by establishing - against the Marcionite understanding - that Marcion lived in the Antonine period (the reasons for doubting this claim are summed up in my quote from Tyson). Then after establishing that the Marcionites say Marcion - not Paul - established the rule of the separation of Law and gospel in a manner which resembles the situation that confronts us from the beginning of to the Galatians before moving on to tackle Paul's role (= the Catholic version of Marcion) in the same controversy.
Indeed this is where we can begin to see the underlying deceptiveness of Tertullian's strategy in Book One. For at the beginning of chapter 20 he acknowledges that the Marcionites put Marcion in the role of Paul (for our tradition) rejecting the adulteration of the gospel - corrupted with 'Judaizing' (we'll leave the meaning of that for now). But in the previous chapter as we noted he goes to great length to show that Marcion is separated from Jesus - not Paul - by over a hundred years. Why is that? Why doesn't Tertullian say Marcion is separated from Paul by a century? Wouldn't that make more sense given the context?
I think the reason for this is plain when you read on from chapter 19 to 20 to 21 and what follows. Even though the real point of the exercise is to refute the Marcionite assumption that Marcion was 'the head of the apostles' (as Marutha) Tertullian is extremely clever and subtle about it. He got the ideas from Irenaeus no doubt. What he does is effectively to (a) let the Marcionites speak as they do (i.e. in terms of 'Marcion' doing this or that in Galatians) but rebut their claims with the Catholic interpretation of the same material (i.e. 'Paul' doing this or that in Galatians). Then when this established the reason for distinguishing between the alleged dates from Jesus to Marcion make the Marcionite interpretation of Galatians seem to be an innovation with no need for being taken seriously. Look again:
They allege that in separating the Law and the Gospel Marcion did not so much invent a new rule as refurbish a rule previously debased (= Paul in Galatians for a Catholic). So then Christ, our most patient Lord, has through all these years borne with a perversion of the preaching about himself, until, if you please, Marcion should come to his rescue (= Paul is called in Galatians to preserve the truth of the gospel). They object that Peter and those others, pillars of the apostleship, were reproved by Paul (= notice the sudden change) for not walking uprightly according to the truth of the gospel—by that Paul, you understand (ab illo certe Paulo or 'by that very Paul') who, yet inexperienced in grace, and anxious lest he had run or was running in vain, was then for the first time conferring with those who were apostles before him.
The point here clearly is that the question of whether it was Marcion or Paul who was at that narrative in Galatians. This is why Tertullian here puts forward Paul's presence as if it were controversial - i.e. that it was Paul rather than Marcion who was opposed by Peter and the other pillars). All that immediately follows builds on this distinction - i.e. because it was really Paul rather than Marcion who did these things the text should be understood completely differently
So then if, as still a neophyte, in his zeal against Judaism he thought something in their conduct called for reproof, their indiscriminate associations in fact, though he himself was afterwards to become in practice all things to all men—to the Jews as a Jew, to those under the law as himself under the law—do you allege that that reproof, concerning conduct and nothing more, conduct which its critic was afterwards to approve of, must be supposed to refer to some deviation in their preaching concerning God? On the contrary, in respect of the unity of their preaching, as we have read earlier in this epistle, they had joined their right hands, and by the very act of having divided their spheres of work had signified their agreement in the fellowship of the gospel: as he says in another place, Whether it were I or they, so we preach.
Also, although he writes of how certain false brethren had crept in unawares, desiring to remove the Galatians to another gospel, he himself shows clearly that that adulteration of the gospel was not concerned with diversion of the faith towards another god and another Christ, but with adherence to the regulations of the law. In fact he found them insisting on circumcision, and observing the seasons and days and months and years of those Jewish solemnities which they ought to have known were now revoked in accordance with the reforming ordinance of that Creator who had of old taught of this very thing by his prophets ... So then, in commending this sort of circumcision and this sort of fallow, the apostle was expressing disapproval of those antiquated solemnities ... Now if even their Creator had long ago rejected all these, and the apostle's pronouncement was that they must now be rejected, evidently the fact that the apostle's judgement is in agreement with the Creator's decrees, proves that no other god was the subject of the apostle's preaching, but only he whose decrees the apostle was anxious should now be acknowledged, while in this behalf he stigmatized as false apostles and false brethren such as should divert the Gospel of the Creator'sChrist from the newness which the Creator had foretold, to the oldness which the Creator had rejected.
The point is that both Marcionites and Catholics agree that Marcion was responsible for the antitheses between Law and gospel but the Marcionites went so far as to read Marcion as being present in the narrative of Galatians - i.e. as the very 'apostle' in the place of our Paul with all his assumptions. The Catholics could get away with these substitutions because, as Tertullian confesses in Book Five, they kept the identity of their 'apostle' (i.e. Marcion) hidden.
