“Lord, now let your servant depart in peace, according to your word; for my eyes have seen your salvation which you prepared in the presence of all peoples, a light for revelation to the Gentiles, and for glory to your people Israel.” (St. Simeon, Luke 2:29-32)
“In the Old Testament, Moses entered into that light, that luminous cloud on the mountaintop. In Exodus, when Moses is coming down from the mountain, his face is shining with the light, and they have to put a veil over his face because people could not look at him (see Ex. 34:29–35). In the synoptic Gospels, at the Transfiguration, Jesus goes up on Mt. Tabor with Peter, James, and John and is transfigured, shining with the uncreated light. The disciples see Him, but they have to hide their faces (see Matt. 17:1–9; Mark 9:2–10; Luke 9:28–36).
These passages show the real, divine light that is in the world, a light that human beings can actually experience. We can know it and see it, and as creatures we can participate in it. The mystical saints, when speaking of this light, name it Jesus. If there are holy and righteous people anywhere who have pure hearts and seek the true God, God in His mercy may reveal to them His divine light.
We, as Christians, would say it is Jesus Christ they see. The others may not know it is Jesus, but we do. This glory St. John speaks about—“we have beheld his glory” (John 1:14)—is the uncreated splendor of God that Moses, Elijah, and Isaiah in the temple saw in the Old Testament.
It is the light St. Paul saw when he was struck down on the road to Damascus. This light of God, we Christians confess, is hypostatically, personally, Jesus Christ. Not only does this light shine from Jesus’ face in the Transfiguration, but in St. John’s Gospel Jesus says, ‘I am this Light.‘ Jesus Christ is the Light and the source of light.”
(Thomas Hopko, The Names of Jesus: Discovering the Person of Christ through Scripture, Kindle Location 2855-2866)