After this he returns to the subject of Marcion's opinions (having already spoken frequently of them), and states some of them correctly, while others he has misunderstood; these, however, it is not necessary for us to answer or refute. Again, after this he brings forward the various arguments that may be urged on Marcion's behalf, and also against him, enumerating what the opinions are which exonerate him from the charges, and what expose him to them; and when he desires to support the statement which declares that Jesus has been the subject of prophecy—in order to found a charge against Marcion and his followers—he distinctly asks, “How could he, who was punished in such a manner, be shown to be God's Son, unless these things had been predicted of him?”
He next proceeds to jest, and, as his custom is, to pour ridicule upon the subject, introducing “two sons of God, one the son of the Creator, and the other the son of Marcion's God; and he portrays their single combats, saying that the Theomachies of the Fathers are like the battles between quails; or that the Fathers, becoming useless through age, and falling into their dotage do not meddle at all with one another, but leave their sons to fight it out.” The remark which he made formerly we will turn against himself: “What old woman would not be ashamed to lull a child to sleep with such stories as he has inserted in the work which he entitles A True Discourse?
For when he ought seriously to apply himself to argument, he leaves serious argument aside, and betakes himself to jesting and buffoonery, imagining that he is writing mimes or scoffing verses; not observing that such a method of procedure defeats his purpose, which is to make us abandon Christianity and give in our adherence to his opinions, which, perhaps, had they been stated with some degree of gravity, would have appeared more likely to convince, whereas since he continues to ridicule, and scoff, and play the buffoon, we answer that it is because he has no argument of weight (for such he neither had, nor could understand) that he has betaken himself to such drivelling.”
Source: Against Celsus (New Advent)