Tertullian — Against Marcion 1.2
The Pontic brings in two gods, as if two Symplegades of his own shipwreck: the one he could not deny—that is the Creator, that is ours—and the one he will not be able to prove—that is his—having suffered, unhappy man, the impulse of this presumption from a simple chapter of the Lord’s pronouncement, which sets those examples of the good and bad tree for humans, not for gods: that neither a good tree brings forth bad fruits nor a bad good—that is, that neither a good mind or faith produces bad works nor a bad good ones.
For growing weak—as even now many do, and especially heretics—around the question of evil, whence evil, and with senses dulled by the very enormity of curiosity, finding the Creator pronouncing: I am he who creates evils, the more he had presumed him author of evil also from other arguments that so persuade every perverse person, the more, interpreting the Creator as the bad tree producing bad fruits—namely evils—he presumed there ought to be another god on the side of the good tree’s good fruits. And so, finding in Christ as it were another disposition of sole and pure kindness, as different from the Creator’s, he easily argued a new and guest divinity revealed in his Christ, and from a little yeast thereafter he flavored the whole lump of faith with heretical sourness.
He also had a certain Cerdo as informer of this scandal: two blind men more easily thought they had seen through two gods. For they had not seen one whole. Even to bleary eyes a single lamp is numerous. Therefore the one god whom he was compelled to confess he destroyed by defaming him from evil; the other whom he was striving to invent he constructed by preferring him from good. By what articles he disposed these natures we will show through our very replies.
Latin
Duos Ponticus deos adfert, tamquam duas Symplegadas naufragii sui, quem negare non potuit, id est creatorem, id est nostrum, et quem probare non poterit, id est suum, passus, infelix, huius praesumptionis instinctum de simplici capitulo dominicae pronuntiationis, in homines non in deos disponentis exempla illa bonae et malae arboris, quod neque bona malos neque mala bonos proferat fructus, id est neque mens uel fides bona malas edat operas neque mala bonas. languens enim — quod et nunc multi, et maxime haeretici — circa mali quaestionem, unde malum, et obtusis sensibus ipsa enormitate curiositatis inueniens creatorem pronuntiantem: ego sum, qui condo mala, quanto ipsum praesumpserat mali auctorem et ex aliis argumentis, quae ita persuadent peruerso cuique, tanto in creatorem interpretatus malam arborem malos fructus condentem, scilicet mala, alium deum praesumpsit esse debere in partem bonae arboris bonos fructus. et ita in Christo quasi aliam inueniens dispositionem solius et purae benignitatis, ut diuersae a creatoris, facile nouam et hospitam argumentatus est diuinitatem in Christo suo reuelatam modicoque exinde fermento totam fidei massam haeretico acore desipuit. habuit et Cerdonem quendam informatorem scandali huius: duo facilius duos deos caeci perspexisse se existimauerunt. unum enim non integre uiderant. lippientibus etiam singularis lucerna numerosa est. alterum igitur deum, quem confiteri cogebatur, de malo infamando destruxit, alterum, quem commentari conitebatur, de bono praeferendo construxit. has naturas quibus disposuerit articulis, per ipsas responsiones nostras ostendemus.