Irenaeus on the Heretical Teachings of Marcion in 180CE

Marcion of Pontus … advanced the most daring blasphemy against Him who is proclaimed as God by the law and the prophets, declaring Him to be the author of evils, to take delight in war, to be infirm of purpose, and even to be contrary to Himself. But Jesus being derived from that father who is above the God that made the world … was manifested in the form of a man to those who were in Judea, abolishing the prophets and the law, and all the works of that God who made the world, whom also he calls Cosmocrator. Besides this, he mutilates the Gospel which is according to Luke, removing all that is written respecting the generation of the Lord, and setting aside a great deal of the teaching of the Lord. …

In addition to his blasphemy against God Himself, he advanced this also, truly speaking as with the mouth of the devil, and saying all things in direct opposition to the truth—that Cain, and those like him, and the Sodomites, and the Egyptians, and others like them, and, in fine, all the nations who walked in all sorts of abomination, were saved by the Lord, on His descending into Hades, and on their running unto Him, and that they welcomed Him into their kingdom. …

For all those who are of a perverse mind, having been set against the Mosaic legislation, judging it to be dissimilar and contrary to the doctrine of the Gospel, have not applied themselves to investigate the causes of the difference of each covenant. Since, therefore, they have been deserted by the paternal love, and puffed up by Satan, being brought over to the doctrine of Simon Magus, they have apostatized in their opinions from Him who is God, and imagined that they have themselves discovered more than the apostles, by finding out another god; and [maintained] that the apostles preached the Gospel still somewhat under the influence of Jewish opinions, but that they themselves are purer [in doctrine], and more intelligent, than the apostles.

Therefore also Marcion and his followers have taken themselves to mutilating the Scriptures, not acknowledging some books at all; and, curtailing the Gospel according to Luke and the Epistles of Paul, they assert that these are alone authentic, which they have themselves thus shortened. … But all the rest, inflated with the false name of “knowledge,” do certainly recognize the Scriptures; but they pervert the interpretations, as I have shown in the first book.