Tertullian, Against Marcion 1.21
But if, as one preaching a new god, he wanted to shut out the old god’s law, why does he prescribe nothing about a new god but only about the old law—unless because, faith remaining in the Creator, his law alone had to give way? As that psalm had also sung beforehand: Let us break their bonds from us and cast off their yoke from us—from which of course the nations raged and peoples devised empty things, kings of the earth stood by and rulers gathered as one against the Lord and against his Christ.
And surely if another god were being preached by Paul there would be no debate whether to keep a law or not—one of course not belonging to a new lord and rival of the law. For the very newness and diversity of the god would have removed not only the question of an old and alien law but every mention of it. But this was the whole status of the question: why, when the same god of the law was being preached in Christ, his law was being derogated from.
Faith therefore always stood in the Creator and his Christ, but conduct and discipline wavered. For some disputed about eating idol-food, others about women’s veiling, others about marriages or divorces, some even about hope of resurrection—about God, no one. For if this question too had been disputed, it also would be found in the apostle, and how much more as principal.
But if after the apostles’ times truth suffered adultery around the rule of God, then already apostolic tradition suffered nothing in its own time around the rule of God, and no other tradition of the apostles is to be recognized than what is issued today among their own churches. You will find moreover no church of apostolic census that does not christianize in the Creator. Or if these were corrupted from the start, which will be intact?—doubtless the Creator’s adversaries. Exhibit therefore some one from yours of apostolic census, and you will have won.
Therefore since it stands in every way that from Christ until Marcion no other god was in this sacrament’s rule than the Creator, our proof is already fortified enough by which we showed the heretic god’s notice began from separating gospel and law, and the earlier definition is equipped: a god is not to be believed whom a man composed from his own senses unless plainly a prophet—that is, not from his own senses. If Marcion can be called that, he will also have to be proved. For by this wedge of truth every heresy is driven out when Christ is shown a carrier of no other god than the Creator.
Latin
Ceterum si, qua nouum deum praedicans, ueteris dei legem cupiebat excludere, quare de deo quidem nouo nihil praescribit, sed de uetere lege solummodo, nisi quoniam fide manente in creatorem sola lex eius concessare debebat? ut et psalmus ille praececinerat: disrumpam ua a nobis is uincula eorum et abiciamus eorum iugum a nobis; ex quo scilicet tumultuatae sunt gentes et populi meditati sunt inania, adstitel\'unt reges terrae et magi stratus conuenerunt in unum aduersus dominum et aduersus Christum eius. et utique, si alius deus praedicaretur a Paulo, nulla disceptatio esset seruandae legis necne, non pertinentis scilicet ad dominum nouum et aemulum legis. ipsa enim dei nouitas atque diuersitas abstulisset non modo quaestionem ueteris et alienae legis uerum omnem eius mentionem. sed hic erat totus status quaestionis, quid, cum idem deus legis in Christo praedicaretur, legi eius derogaretur. stabat igitur fides semper in creatore et Christo eius, sed conuersatio et disciplina nutabat. nam et alii de idolothyto edendo, alii de mulierum uelamento, alii de nuptiis uel repudiis, nonnulli et de spe resurrectionis disceptabant, de deo nemo. nam (si) fuisset haec quoque quaestio disceptata, et ipsa apud apostolum inueniretur, uel quanto principalis. quodsi post apostolorum tempora adulterium ueritas passa est circa dei regulam, ergo iam apostolica traditio nihil passa est in tempore suo circa dei regulam, et non alia agnoscenda erit traditio apostolorum quam quae hodie apud ipsorum ecclesias editur. nullam autem apostolici census ecclesiam inuenias, quae non in creatore christianizet. aut si hae erunt a primordio corruptae. quae erunt integrae? nimirum aduersariae creatoris. exhibe ergo aliquam ex tuis apostolici census, et obduxeris. igitur cum omnibus modis constet alium deum in regula sacramenti istius non fuisse a Christo usque ad Marcionem quam creatorem, satis iam et probatio nostra munita est, qua ostendimus notitiam dei haeretici ex euangelii et legis separatione coepisse, et definitio superior instructa est, non esse credendum deum, quem homo de suis sensibus composuerit, nisi plane prophetes. id est non de suis sensibus. quod si Marcion poterit dici, debebit etiam probari; ** nihil retractare oportebit. hoc enim cuneo ueritatis omnis extruditur haeresis, cum Christus non alterius dei quam creatoris circumlator ostenditur.