107 God alone, who is derived from nothing and from whom all things are derived, is a wholly simple and individual essence… Therefore an angel is not unity itself, or else he would be God, or there would be many gods, which cannot even be conceived. For what will be one if not a unity? It is left for an angel to be a number. But if it is, it is a number in one aspect and a multiplicity in another. Every number, however, is imperfect insofar as it is a multiplicity, but perfect so far as it is one. Therefore, whatever is imperfect in an angel let us ascribe to the angels’ multiplicity, which it has from being a number, that is, a creature; and whatever is perfect to its participation in unity, which it has from being associated with God.
In an angel we find a double imperfection: the one, that it is not being itself but only an essence to which being comes by participation, so that it may be; the other, that it is not intelligence itself but only happens to understand, since by its nature it is an intellect capable of understanding. The second imperfection, however, depends on the first, since what does not exist of itself, certainly does not understand by itself, since there can be nothing where being itself is not. Therefore both of these imperfections befall an angel insofar as it is a multiplicity. It remains for its perfection and completion to be produced by unity coming from above. God is the unity from which angels draw their being, their life, and all their perfection.
Any number, after unity, is perfected and completed by unity. Unity along, completely simple, perfected by itself, does not go beyond itself but in its individual and solitary simplicity is composed of itself, since it is self-sufficient, in want of nothing, and full of its own riches. Since number by its nature is manifold, it is simple--so for as it is capable of simplicity--only by virtue of unity; and although every number falls into ever greater multiplicity the further it is removed from unity, and the more diversity, the more parts, and the more compoundness there is in it; nevertheless, none is so close to unity as not to be a multiple, having only an accidental unity and being one not by nature but by composition.
Let us apply these notions to divine things, after the Pythagorean custom. God alone, who is derived from nothing and from whom all things are derived, is a wholly simple and individual essence. Whatever he has, he has from himself. For the same reason that he exists, he knows, wills, and is good and just. We cannot understand any reason why he exists except that he is being itself. Other things are not being itself, but exist by means of it.
109 An angel, from what we have said, has perfectly realized his own nature and intellectual qualities. Nevertheless, he does not have a way to fulfill his functions of understanding and contemplation unless he is first surrounded by God with intelligible forms. For this reason the darkness has hitherto been upon the face of the deep.