It seems to me that this happens when the soul falls in love with what is beautiful by nature. Hope is always drawing it from the beauty it has already seen toward the beauty still beyond it. Everything it reaches kindles an even stronger desire for what remains hidden. So the passionate lover of beauty receives whatever is continually revealed as an image of what he desires, yet longs to be filled with the very form of the original itself.
This is what the bold request, which passes beyond the ordinary limits of desire, is asking for: not to enjoy beauty through mirrors and reflections, but face to face. Yet the divine voice gives what was asked precisely through what it refuses, opening in a few words an immeasurable depth of meaning. God’s great generosity agrees to fulfill the desire, but He does not promise that the longing will ever stop or be satisfied.
For God would not have shown Himself to His servant if what was seen could bring the desire of the one looking to an end. True sight of God consists in this: the person who looks toward Him never ceases to desire Him. For He says, “You cannot see My face, for no one shall see My face and live.”
The passage does not mean that God’s face causes death to those who see it. How could the face of Life ever cause death to those who approach it? Rather, God gives life by nature, and the divine nature lies beyond every mark by which something can be known. Anyone who thinks that God is one of the things we can know has turned away from what truly exists toward something the mind has imagined, and therefore does not have life.
What truly exists is true life, and true life cannot be reached by knowledge. If the life-giving nature lies beyond knowledge, then whatever the mind can fully grasp is certainly not life. And what is not life cannot give life. In this way Moses receives what he longs for precisely because his desire remains unfulfilled.
He is taught from this that God, by His own nature, has no limit and is enclosed by no boundary. If we imagined God ending at some boundary, we would also have to imagine whatever lies beyond that boundary, since anything bounded must end in something else. Creatures that live on land are bounded by the air around them, and creatures that live in water by water. A fish is surrounded on every side by water, and a bird by air. At the surface of each creature, the creature ends and the surrounding water or air begins. In the same way, if God were thought to have a boundary, He would have to be enclosed by something of a different nature. And the thing that contains another must be greater than what it contains.
But it is acknowledged that God is Good by nature. Whatever is of a different nature from the Good must be something other than good, and what lies outside the Good belongs to the nature of evil. We have already shown that what contains something is greater than what it contains. Therefore, anyone who imagines God within a boundary is forced to agree that God is enclosed by evil.
Since whatever is contained is less than what contains it, the greater would then have dominion over the lesser. So anyone who confines God within a boundary ends up making the Good subject to its opposite. But that is absurd. We should therefore think of the invisible nature as having no enclosing boundary. And what cannot be enclosed cannot be fully grasped. Every desire for the Good that draws the soul into this ascent therefore keeps stretching forward as the soul moves toward the Good.
This is what it truly means to see God: never to find an end to the desire for Him. We must always look through whatever means of seeing are available to us and let what we see kindle the desire to see still more. In this way no boundary can stop our ascent toward God, because the Good has no limit and no satisfaction can bring our desire for the Good to an end.