Tertullian, Against Marcion 4.30
How did he take apart the question of the Sabbath cure? "Doesn't each of you on the Sabbath untie his donkey or ox from the manger and lead it to water?" (Matthew 12:11). So, working within the law's own terms, he confirmed the law instead of abolishing it—the law that commands no work be done except what serves any living soul, how much more a human one? I see that parables must match up at every point. "The kingdom of God is like a mustard seed that a man took and sowed in his garden" (Luke 13:18-19; Mark 4:30-32). Who is the "man"? Clearly Christ, who even on Marcion's terms is called the Son of Man. He received the kingdom's seed—the gospel message—from the Father and sowed it in his garden, this world. Now suppose the "man" is a human being; but when Jesus says "his garden," neither the world nor the man belongs to him—both belong to the Creator. So the one who sows in his own garden is shown to be the Creator's. Or if, to dodge this trap, they shift the "man" from Christ to a human who receives the kingdom's seed and sows it in the garden of his heart, even that scenario fits no one but the Creator.
Latin
Quaestionem rursus de curatione sabbatis facta quomodo discussit? unusquisque uestrum sabbatis non soluits asinum aut bouem suum a praesepi et ducit ad potum? ergo secundum condicionem legis operatus legem confirmauit, non dissoluit, iubentem nullum opus fieri, nisi quod fieret omni animae, quanto potius humanae? Parabolarum congruentiam ubique recognoscor exigere. simile est regnum dei, inquit, grano sinapis, quod accepit homo et seminauit in horto suo. quis in persona hominis intellegendus? utique Christus, qui, licet Marcionis, filius hominis est dictus, qui accepit a patre semen regni, sermonem scilicet euangelii, et seminauit in horto, isto utique in mundo. puta nunc in homine, sed cum in (suo) horto dixerit nec mundus autem nec homo illius sit, sed creatoris, ergo qui in suum seminarit creatoris ostenditur. aut si, ut hunc laqueum euadant, conuerterint hominis personam a Christo in hominem accipientem semen regni et seminantem in horto cordis sui, nec ipsa materia alii conueniet quam creatori.