6 Why was it, too, that, beholding the angels along with the Saviour, she did indeed conceive their images, but not that of the Saviour, who is far more beautiful than they? Did He not please her; and did she not, on that account, conceive after His likeness? How was it, too, that the Demiurge, whom they can call an animal being, having, as they maintain, his own special magnitude and figure, was produced perfect as respects his substance; while that which is spiritual, which also ought to be more effective than that which is animal, was sent forth imperfect, and he required to descend into a soul, that in it he might obtain form, and thus becoming perfect, might be rendered fit for the reception of perfect reason?
If, then, he obtains form in mere earthly and animal men, he can no longer be said to be after the likeness of angels whom they call lights, but [after the likeness] of those men who are here below. For he will not possess in that case the likeness and appearance of angels, but of those souls in whom also he receives shape; just as water when poured into a vessel takes the form of that vessel, and if on any occasion it happens to congeal in it, it will acquire the form of the vessel in which it has thus been frozen, since souls themselves possess the figure of the body [in which they dwell]; for they themselves have been adapted to the vessel [in which they exist], as I have said before.
If, then, that seed [referred to] is here solidified and formed into a definite shape, it will possess the figure of a man. and not the form of the angels. How is it possible, therefore, that that seed should be after images of the angels, seeing it has obtained a form after the likeness of men? Why, again, since it was of a spiritual nature, had it any need of descending into flesh? For what is carnal stands in need of that which is spiritual, if indeed it is to be saved, that in it it may be sanctified and cleared from all impurity, and that what is mortal may be swallowed up by immortality; but that which is spiritual has no need whatever of those things which are here below. For it is not we who benefit it, but it that improves us.
Source: Adversus haereses (New Advent)