That human being who is inwardly illumined by the light of the Holy Spirit cannot endure the vision of it, but falls face down on the ground and cries out in great fear and wonder, because he has seen and experienced something that is beyond nature, thought, or conception. He becomes like someone suddenly inflamed with a violent fever; as though on fire and powerless to control the flames, he is beside himself, totally incapable of controlling himself. And though he weeps incessant tears that bring some relief, the flame of his desire breaks out even more intensely. Then his tears flow even more abundantly and washed by their flow, he becomes even more radiant. When, utterly incandescent, he has become like light, then the saying of Saint Gregory of Nazianzos is fulfilled, "God is united with gods and known by them" in the sense perhaps that he is now united to those who have joined themselves to him, and revealed to those who have come to know him.

(Saint Symeon the New Theologian)