Peter, James and John are given a wonderful grace - they are able to physically see with the eyes of contemplation. In other words, the sights of heightened contemplation were given to ordinary eyes. Ordinary human eyesight without the mysterious workings of God cannot see this extraordinary manifestation of the God-Man. They are also able to hear with the ears of the heart a Voice which says: "This is My beloved Son in Whom I am well pleased; listen to Him" (Matthew 17:5). The limited ability of the human sense of hearing cannot hear the Father speak, unless the Father wills it.
By seeing Moses and Elijah, these three apostles are not only seeing two heroes of the past in salvation history, but as the Law-man and Prophet-man converse with our Lord, it becomes apparent that this transfigured Man is also the very God that Moses and Elijah conversed with during their earthly pilgrimage. The apostles are scared out of their wits - and who wouldn't be!
As we reflect on this story of the Transfiguration, not only can we reflect on the mystery of Jesus - God, Son of God, Son of Mary - we also learn something about the mystery of humanity: if we strive to grow intimately closer to Jesus through ceaseless prayer, that is also the beginning of our own transfiguration. The Face of Jesus which illuminates like the sun, dwells within our soul. He is the Light of our soul.
Jesus is at the controls of contemplation. He is the One Who leads us up the mountain of contemplation. He is the One Who begins our contemplation; He is the One Who decides what will happen during contemplation; and He is the One Who decides how long it will last, that is, when it is time to go back down the mountain, taking the fruits of contemplation into our ordinary lives. Prayerful souls long to "see Him just as He is" (1 John 3:2).
The great heights of contemplation granted to Peter, James and John might be called, as used in an Ambrosian hymn, "sobriam ebrietatem" - "sober intoxication". Dom Nicholas Kempf, in his work titled, "Expositiones Mysticæ Cantica Canticorum" explains sober intoxication as a heart that has been moved to jubilation that is utterly mysterious and completely inexpressible.
Saint Gregory Palamas wrote: "Let us, considering the Mystery of the Transfiguration of the Lord, strive to be illumined by this Light ourselves and encourage in ourselves love and striving towards the Unfading Glory and Beauty, purifying our spiritual eyes of worldly thoughts and refraining from perishable and quickly passing delights and beauty which darken the garb of the soul."
"Towards the transfiguration of Love, in the joy of the Spirit . . . listen, listen, in a world that leaves God . . . declare in silence: The thirst of happiness that steps across you all, only He may quench it!" (I Colori del Silenzio).