3. If two things, not previously united, come afterwards to be united, this must be either by a change in both or by a change in one of them. If therefore any created intellect begins anew to see the essence of God, the divine essence must be conjoined anew with that intellect by way of intelligible presentation. But it is impossible for the divine essence to change; and therefore such union must begin by some change in the created intellect, that is to say, by its making some new acquisition.
But because we arrive at the knowledge of things intelligible through things sensible, we also transfer the names of sensible cognition to intelligible cognition, and particularly the properties of sight, which among senses is the nobler and more spiritual and more akin to intellect: hence intellectual knowledge itself is called sight, or vision. And because bodily vision is not accomplished except through light, the means whereby intellectual vision is fulfilled borrow the name of light. That disposition therefore whereby a created intelligence is raised to the intellectual vision of the divine substance is called the 'light of glory.'
This is the light of which it is said: In thy light we shall see light (Ps. xxxv, 10), to wit, of the divine substance; and, The city needeth not sun nor moon, for the brightness of God illuminateth it (Apoc. xxi, 23); and, No more shall there be sun to shine on thee by day, nor brightness of moon to enlighten thee, but the Lord shall be to thee an everlasting light, and thy God shall be thy glory Isaias lx, 19). And because in God being and understanding are the same and He is to all the cause of understanding, He is on that account called 'light': He was the true light, that enlighteneth every man coming into this world John i, 8)*: God is light (1 John i, 5): Clad in light as in a garment (Ps. ciii, 2). And therefore also as well God as the angels in Holy Scripture are described in figures of fire, because of the brightness of fire.
3.52 : That no Created Substance can of its Natural Power arrive to see God as He essentially is
3.54 : Arguments against the aforesaid Statements and their Solutions