By His Transfiguration, the Lord showed His disciples how He was going to come on the last day in the glory of His Divinity and in the body of His humanity.
He led them up the mountain to show them Who the Son is and Whose He is. Because when He asked them, ‘Whom do men say the Son of man is?’ They said to Him, some Elias, others Jeremiah, or one of the Prophets. This is why He leads them up the mountain and shows them that He is not Elias, but the God of Elias; again, that He is not Jeremiah, but the One Who sanctified Jeremiah in his mother’s womb; not one of the Prophets, but the Lord of the Prophets, Who also sent them. And He shows them that He is the maker of heaven and earth, and that He is Lord of living and dead. For He gave orders to heaven and brought down Elias, and made a sign to the earth and raised up Moses.
He led them up the mountain to show them that he is the Son of God, born from the Father before the ages and in the last times incarnate from the Virgin, as he knows how, born ineffably and without seed, preserving her virginity incorrupt; for wherever God wills it, the order of nature is overcome. For God the Word dwelt in the Virgin’s womb, and the fire of his divinity did not consume the members of the Virgin’s body, but protected them carefully by its nine month presence. He dwelt in the Virgin’s womb, not abhorring the unpleasant smell of nature, and God incarnate came forth from her to save us.
He led them up the mountain to show them the glory of the godhead and to make known to them that he is the redeemer of Israel, as he had shown through the Prophets, and they should not be scandalized in him when they saw his voluntary sufferings, which as man he was about to suffer for us. For they knew him as a man, but did not know that he was God. They knew him as son of Mary, going about with them in the world, and he made known to them on the mountain that he was Son of God and God. They saw that he ate and drank, toiled and rested, dozed and slept, things which did not accord with his divine nature, but only with his humanity, and so he took them to the mountain that the Father mijeght call him Son and show that he is truly his Son and that he is God.
He led them up the mountain and showed them his kingship before his passion, and his power before his death, and his glory before his disgrace, and his honor before his dishonor, so that, when he was arrested and crucified by the Jews, they might know that he was not crucified through weakness, but willingly by his good pleasure for the salvation of the world.
He led them up the mountain and showed the glory of his divinity before the resurrection, so that when he rose from the dead in the glory of his divine nature, they might know that it was not because of his harsh toil that he accepted glory, as if he lacked it, but it was his before the ages with the Father and together with the Father, as he said as he was coming to his voluntary passion, ‘Father, glorify me with the glory which I had with you before the world existed’. And so on the mountain he showed his Apostles the glory of his divinity, concealed and hidden by his humanity. For they saw his face bright as lightning and his garments white as light.
Translated by The Catalog of Good Deeds
