To this it may first be answered that the indeterminate should not be scorned everywhere, nor that which is conceived of as shapeless, even if this be the substrate of the higher and better entities; for we might call even the soul indeterminate, in respect to intelligence and reason, which give it a better shape and nature. Besides, when we say that intelligible things are composite (of matter and form), this is not in the sense in which the word is used of bodies. Even reasons would thus be called composite, and by their actualization form another alleged composite, nature, which aspires to form. If, in the intelligible world, the composite tend toward some other principle, or depend thereon, the difference between this composite and bodies is still better marked. Besides, the matter of begotten things ceaselessly changes form, while the matter of the intelligible entities ever remains identical. Further, matter here below is subject to other conditions (than in the intelligible world). Here below, indeed, matter is all things only partly, and is all things only successively; consequently, amidst these perpetual changes nothing is identical, nothing is permanent. Above, on the contrary, matter is all things simultaneously, and possessing all things, could not transform itself. Consequently, matter is never shapeless above; for it is not even shapeless here below. Only the one (intelligible matter) is situated differently from the other (sense-matter). Whether, however, (intelligible matter) be begotten, or be eternal, is a question that cannot be determined until we know what it is. [Ennead II,4 (12) 3]
How do Guardians participate in matter, and of what matter are they formed? This their matter is not corporeal, otherwise they would be animals with sensation. In fact, whether they have aerial or fire-like bodies, they must have had a nature primitively different (from pure Intelligence) to have ultimately united each with his own body, for that which is entirely pure could not have immediately united with a body, although many philosophers think that the being of every Guardian, as guardian, is united to an air-like or fire-like body. But why is the being of every Guardian mingled with a body, while the being of every deity is pure, unless in the first case there be a cause which produces the mingling (with matter)? This cause must be the existence of an intelligible matter, so that whatever participates in it might, by its means, come to unite with sense-matter. [Ennead III,5 (50) 6]