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

For the one, as it gives subsistence to all things, so likewise it is the cause of the participated unities, and of beings suspended from these unities. But the unity belonging to every being produces the peculiarity which shines forth in that particular being. And the one indeed is the cause of existence simply; but unity is the cause of alliance, because it is connascent with the one. Hence, unity is that which of itself defines the being which participates of it, and essentially exhibits in itself a superessential peculiarity. For every where, from that which is primary that which is secondary is that which it is. If, therefore, there is a certain superessential peculiarity of deity, this also belongs to the being which participates of it superessentially.