Innumerable texts of sacred Scripture speak of the light. There are the Johannine writings which tell us that the true light that enlightens everyone was coming into the world. Then there is the blinding light, brighter than the noonday sun, that shattered Paul on the road to Damascus. Again there is the light on the face of Moses, so dazzling that he covered his face with a veil. But most important for Gregory Palamas and the theology that stems from him is the great event called the Transfiguration.
With Peter, James and John, Jesus ascends the mountain and is transfigured before them. Intense light shines from his body and through his clothing, enveloping the disciples so that they share in the light and see his glory.
— William Johnston, Mystical Theology