Irenaeus of Lyons · a new plain-English translation from the original language
How Unstable Is the Pleroma of the Disciples of Valentinus. 1. Unstable, then, is their Bythus, and unstable is his Pleroma, and the God of Marcion. For, as they say, he has outside himself something lying beneath, which they call the Void and the Shadow, and this Void is shown to be greater than their own Pleroma. And it is equally unstable to say this — that even though everything is held within him, this created order was nevertheless fashioned by someone else. For they must necessarily admit some void and formless thing, within which this universe was fashioned, inside the spiritual Pleroma; and they must say of this formless thing either that the Forefather, foreknowing what would come to be in it, deliberately left it so, or that he did not know. If he did not know, then God will no longer be the foreknower of all things; nor will they be able to give any reason why he left this place idle for so long a time. But if he did foreknow it, and beheld in his mind the condition that would come to be in that place, then he himself made it — he who also pre-formed it within himself.
Let them, then, cease to say that the world was made by another; for as soon as God conceived it in mind, that which he had conceived in mind came to be. For it was not possible for one to conceive a thing in mind and another to make what had been conceived by him. But according to these heretics, God conceived the world in mind either as eternal or as temporal, and both suppositions are incredible. For if he conceived it as eternal, both spiritual and visible, then it would also have been made such. But if it is such as it now is, and he who made it had conceived it in mind as such — willing it to exist, in the Father's own presence, according to that mental conception, as composite, changeable, and passing away — then, since it is the Father's own workmanship, and since what was conceived and pre-formed in this way by the Father of all was made just as it was conceived, to call it the fruit of a defect and the offspring of ignorance amounts to blasphemy of the worst sort. For on their own reckoning, the universal Father must then be shown producing, from a thought conceived within his own bosom, emissions born of defect and fruits born of ignorance — given that whatever he had conceived in thought is precisely what resulted.