2 Moreover, he shall also examine the doctrine of Marcion, [inquiring] how he holds that there are two gods, separated from each other by an infinite distance. Or how can he be good who draws away men that do not belong to him from him who made them, and calls them into his own kingdom? And why is his goodness, which does not save all [thus], defective? Also, why does he, indeed, seem to be good as respects men, but most unjust with regard to him who made men, inasmuch as he deprives him of his possessions? Moreover, how could the Lord, with any justice, if He belonged to another father, have acknowledged the bread to be His body, while He took it from that creation to which we belong, and affirmed the mixed cup to be His blood? And why did He acknowledge Himself to be the Son of man, if He had not gone through that birth which belongs to a human being? How, too, could He forgive us those sins for which we are answerable to our Maker and God? And how, again, supposing that He was not flesh, but was a man merely in appearance, could He have been crucified, and could blood and water have issued from His pierced side? What body, moreover, was it that those who buried Him consigned to the tomb? And what was that which rose again from the dead?
3. [This spiritual man] shall also judge all the followers of Valentinus, because they do indeed confess with the tongue one God the Father, and that all things derive their existence from Him, but do at the same time maintain that He who formed all things is the fruit of an apostasy or defect. [He shall judge them, too, because] they do in like manner confess with the tongue one Lord Jesus Christ, the Son of God, but assign in their [system of] doctrine a production of his own to the Only-begotten, one of his own also to the Word, another to Christ, and yet another to the Saviour; so that, according to them, all these beings are indeed said [in Scripture to be], as it were, one; [while they maintain], notwithstanding, that each one of them should be understood [to exist] separately [from the rest], and to have [had] his own special origin, according to his peculiar conjunction. [It appears], then that their tongues alone, forsooth, have conceded the unity [of God], while their [real] opinion and their understanding (by their habit of investigating profundities) have fallen away from [this doctrine of] unity, and taken up the notion of manifold deities—[this, I say, must appear] when they shall be examined by Christ as to the points [of doctrine] which they have invented. Him, too, they affirm to have been born at a later period than the Pleroma of the Æons, and that His production took place after [the occurrence of] a degeneracy or apostasy; and they maintain that, on account of the passion which was experienced by Sophia, they themselves were brought to the birth. But their own special prophet Homer, listening to whom they have invented such doctrines, shall himself reprove them, when he expresses himself as follows:—
“Hateful to me that man as Hades' gates,
Who one thing thinks, while he another states.”
[This spiritual man] shall also judge the vain speeches of the perverse Gnostics, by showing that they are the disciples of Simon Magus.
Source: Adversus haereses (New Advent)