The Six Books of Proclus on the Theology of Plato, Volume 2

For that it is indeed simple, is evident from its union; since every thing divine is most unical. But a thing of this kind is transcendently simple. That it is also most sufficient to itself, may be learnt by considering that a composite nature is indigent, if not of other things to which it is external, yet of those things of which it is composed. But that which is most simple and unical, and which establishes itself in the good, is most sufficient to itself. Such, however, is every thing divine. Neither, therefore, is it indigent of other things, existing as goodness itself, nor of things requisite to composition, because it is unical.