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

For if each is a self-perfect unity, but neither being, life, or intellect is a unity, but that which is united, it is evident that every God is beyond each of these. For if these differ from each other, but all are in all, each of these being all will not be one only. Farther still, if the first God is superessential, but every God is of the series of the first, so far as a God, each will be superessential. But that the first God is superessential,[261] is evident. For essence is not the same with unity, nor is to exist the same thing as to be united. If, however, these are not the same, either the first God is both these, and in this case he will not be one only, but something else besides the one, and will participate of unity, but will not be the one itself; or he is one of these. But if indeed he is essence, he will be indigent of the one. It is, however, impossible that the good, and the first should be indigent. Hence, he is one alone; and therefore superessential. But if each thing imparts the peculiarity of that which it is primarily to the whole series [of which it is the leader], hence, every divine number is superessential; since every principal cause produces similars prior to dissimilars. If, therefore, the first God is superessential, all the Gods will be superessential. For they will be entirely similar [to the first]. Since, however, they are also essences, they will be produced from the first essence, as the monads of essences.