Tertullian on the Valentinians:
Meanwhile you must believe that Sophia has the surnames of earth and of Mother--"Mother-Earth," of course--and (what may excite your laughter still more heartily) even Holy Spirit. In this way they have conferred all honour on that female, I suppose even a beard, not to say other things. Besides, the Demiurge had so little mastery over things, on the score, you must know, of his inability to approach spiritual essences, (constituted as he was) of animal elements, that, imagining himself to be the only being, he uttered this soliloquy: "I am God, and beside me there is none else." But for all that, he at least was aware that he had not himself existed before. He understood, therefore, that he had been created, and that there must be a creator of a creature of some sort or other. How happens it, then, that he seemed to himself to be the only being, notwithstanding his uncertainty, and although he had, at any rate, some suspicion of the existence of some creator?
The odium felt amongst them against the devil is the more excusable, even because the peculiarly sordid character of his origin justifies it. For he is supposed by them to have had his origin in that criminal excess of her sorrow, from which they also derive the birth of the angels, and demons, and all the wicked spirits. Yet they affirm that the devil is the work of the Demiurge, and they call him Munditenens (Ruler of the World), and maintain that, as he is of a spiritual nature, he has a better knowledge of the things above than the Demiurge, an animal being. He deserves from them the pre-eminence which all heresies provide him with.
Philosophumena on Valentinus
As, therefore, the primary and greatest power of the animal essence came into existence, an image (of the only begotten Son); so also the devil, who is the ruler of this world, constitutes the power of the material essence, as Beelzebub is of the essence of demons which emanates from anxiety. (In consequence of this,) Sophia from above exerted her energy from the Ogdoad to the Hebdomad. For the Demiurge, they say, knows nothing at all, but is, according to them, devoid of understanding, and silly, and is not conscious of what he is doing or working at. But in him, while thus in a state of ignorance that even he is producing, Sophia wrought all sorts of energy, and infused vigour (into him). And (although Sophia) was really the operating cause, he himself imagines that he evolves the creation of the world out of himself: whence he commenced, saying, "I am God, and beside me there is no other."
Irenaeus on Valentinus
As, then, they represent all material substance to be formed from three passions, viz., fear, grief, and perplexity, the account they give is as follows: Animal substances originated from fear and from conversion; the Demiurge they also describe as owing his origin to conversion; but the existence of all the other animal substances they ascribe to fear, such as the souls of irrational animals, and of wild beasts, and men. And on this account, he (the Demiurge), being incapable of recognising any spiritual essences, imagined himself to be God alone, and declared through the prophets, "I am God, and besides me there is none else."
Irenaeus again in Book Two
Simon Magus was the first who said that he himself was God over all, and that the world was formed by his angels. Then those who succeeded him, as I have shown in the first book,(5) by their several opinions, still further depraved [his teaching] through their impious and irreligious doctrines against the Creator. These [heretics now referred to],(6) being the disciples of those mentioned, render such as assent to them worse than the heathen. For the former "serve the creature rather than the Creator,"(7) and "those which are not gods,"(8) notwithstanding that they ascribe the first place in Deity to that God who was the Maker of this universe. But the latter maintain that He, [i.e., the Creator of this world,] is the fruit of a defect, and describe Him as being of an animal nature, and as not knowing that Power which is above Him, while He also exclaims, "I am God, and besides Me there is no other God."(9) Affirming that He lies, they are themselves liars, attributing all sorts of wickedness to Him; and conceiving of one who is not above this Being as really having an existence, they are thus convicted by their own views of blasphemy against that God who really exists, while they conjure into existence a god who has no existence, to their own condemnation. And thus those who declare themselves "perfect," and as being possessed of the knowledge of all things, are found to be worse than the heathen, and to entertain more blasphemous opinions even against their own Creator.
Excerpta Ex Theodoto
Against Tatian, [3] who says that the words, "Let there be light," [4] are supplicatory. If, then, He is supplicating the supreme God, how does He say, "I am God, and beside me there is none else?"
“Finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind.”
― Miguel de Cervantes Saavedra, Don Quixote