On the Flesh of Christ 2Marcion, Who Would Blot Out the Record of Christ's Nativity, is Rebuked for So Startling a Heresy.

Clearly enough is the nativity announced by Gabriel. But what has he to do with the Creator's angel? The conception in the virgin's womb is also set plainly before us. But what concern has he with the Creator's prophet, Isaiah? He will not brook delay, since suddenly (without any prophetic announcement) did he bring down Christ from heaven. "Away," says he, "with that eternal plaguey taxing of Caesar, and the scanty inn, and the squalid swaddling-clothes, and the hard stable. We do not care a jot for that multitude of the heavenly host which praised their Lord at night. Let the shepherds take better care of their flock, and let the wise men spare their legs so long a journey; let them keep their gold to themselves. Let Herod, too, mend his manners, so that Jeremy may not glory over him. Spare also the babe from circumcision, that he may escape the pain thereof; nor let him be brought into the temple, lest he burden his parents with the expense of the offering; nor let him be handed to Simeon, lest the old man be saddened at the point of death. Let that old woman also hold her tongue, lest she should bewitch the child." After such a fashion as this, I suppose you have had, O Marcion, the hardihood of blotting out the original records (of the history) of Christ, that His flesh may lose the proofs of its reality. But, prithee, on what grounds (do you do this)? Show me your authority. If you are a prophet, foretell us a thing; if you are an apostle, open your message in public; if a follower of apostles, side with apostles in thought; if you are only a (private) Christian, believe what has been handed down to us: if, however, you are nothing of all this, then (as I have the best reason to say) cease to live. For indeed you are already dead, since you are no Christian, because you do not believe that which by being believed makes men Christian,--nay, you are the more dead, the more you are not a Christian; having fallen away, after you had been one, by rejecting what you formerly believed, even as you yourself acknowledge in a certain letter of yours, and as your followers do not deny, whilst our (brethren) can prove it. Rejecting, therefore, what you once believed, you have completed the act of rejection, by now no longer believing: the fact, however, of your having ceased to believe has not made your rejection of the faith right and proper; nay, rather, by your act of rejection you prove that what you believed previous to the said act was of a different character. What you believed to be of a different character, had been handed down just as you believed it. Now that which had been handed down was true, inasmuch as it had been transmitted by those whose duty it was to hand it down. Therefore, when rejecting that which had been handed down, you rejected that which was true. You had no authority for what you did. However, we have already in another treatise availed ourselves more fully of these prescriptive rules against all heresies. Our repetition of them hereafter that large (treatise) is superfluous, when we ask the reason why you have formed the opinion that Christ was not born.