The Six Books of Proclus on the Theology of Plato, Volume 1

But the third, as they say, to the saviour, and let us also following Plato in what remains celebrate the perfective order of the Gods. Because, therefore, the end of the connective order was the finite, [or the bounded] the perfective order has extremes. For the end [or bound] is the extremity. There however indeed the one was said to be the finite, but here it is said to have an extremity, as receiving according to participation that which has the power of terminating many things. And there indeed, the one was end or bound, which also connectedly contains the infinite; but here having an extremity, it will also have a middle and beginning, and will be perfect. For that which receives its completion from all these, is perfect. Here, therefore, the perfection which consists of parts is apparent. For the consummation of the parts, produces the perfect. Moreover, because such a one as this has a middle and extremes, it will have the figure of a circumference, or it will be rectilinear, or it will be mixed [from the right and circular line]. For all these require a middle and extremes; some indeed with simplicity, but others with connexion. Three peculiarities, therefore, again present themselves to our view; the first, indeed, being that which we said was to have extremes; the second, being according to the perfect; and the third, according to figure. And there are also three perfective leaders of wholes; one indeed being intelligible; another, intelligible and intellectual; and the third, intellectual.

The intelligible leader, therefore, is said to have extremes, as being directly arranged under the end of the connective Gods, and in the boundaries of himself intelligibly comprehending all the intellectual orders. But the intelligible and intellectual leader, is defined according to the perfect, comprehending in himself the beginnings, middles, and ends of beings, and giving completion to the middle bond of the whole perfective triad. And the intellectual leader proceeds according to triadic figure, being the cause of bound and divine perfection; and imparting termination to things indefinite, but intellectual perfection to things imperfect. And this triad indeed is produced according to the connective triad. For the end in them is the cause of the possession of the extremity. But it is also produced from itself. For that which has extremes, having become a whole, constitutes the perfect through end [or bound]. But the perfect comprehending beginnings, middles and ends, unfolds figure. And thus the perfective triad proceeds supernally, as far as to the last of things, pervading to all things, and perfecting both whole and partial causes.