Against The Valentinians by Tertullian
Chapter XXIII.--The Relative Positions of the Pleroma The Region of Achamoth, and the Creation of the Demiurge. The Addition of Fire to the Various Elements and Bodies of Nature.
Their most eminent powers, moreover, they confine within the following limits, as in a citadel. In the most elevated of all summits presides the tricenary Pleroma, Horos marking off its boundary line. Beneath it, Achamoth occupies the intermediate space for her abode, treading down her son. For under her comes the Demiurge in his own Hebdomad, or rather the Devil, sojourning in this world in common with ourselves, formed, as has been said above, of the same elements and the same body, out of the most profitable calamities of Sophia; inasmuch as, (if it had not been for these,) our spirit would have had no space for inhaling and ejecting air -- that delicate vest of all corporeal creatures, that revealer of all colours, that instrument of the seasons -- if the sadness of Sophia had not filtered it, just as her fear did the animal existence, and her conversion the Demiurge himself. Into all these elements and bodies fire was fanned. Now, since they have not as yet explained to us the original sensation of this in Sophia, I will on my own responsibility conjecture that its spark was struck out of the delicate emotions of her (feverish grief). For you may be quite sure that, amidst all her vexations, she must have had a good deal of fever.