This work, which establishes Irenaeus as the most important of the theologians of the second century, is a detailed and effective refutation of Gnosticism, and a major source of information on the various Gnostic sects and doctrines. This volume contains Book One. †

These arguments may, in like manner, be adapted to meet the case of all those who, in any way, maintain that the world was formed either by angels or by any other one than the true God. For the charges which they bring against the Demiurge, and those things which were made material and temporal, will in truth fall back on the Father; if indeed the(7) very things which were formed in the bosom of the Pleroma began by and by in fact to be dissolved, in accordance with the permission and good-will of the Father.

It follows then, as of course, that these men must either receive the rest of his narrative, or else reject these parts also. For no persons of common sense can permit them to receive some things recounted by Luke as being true, and to set others aside, as if he had not known the truth. And if indeed Marcion's followers reject these, they will then possess no Gospel; for, curtailing that according to Luke, as I have said already, they boast in having the Gospel [in what remains].

2. If, again, they refer to any cause on account of which their Father does not impart life to bodies, then that cause must necessarily appear superior to the Father, since it restrains Him from the exercise of His benevolence; and His benevolence will thus be proved weak, on account of that cause which they bring forward. Now every one must perceive that bodies are capable of receiving life. For they live to the extent that God pleases that they should live.