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 Jeremias, 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 Jeremias, but the one who sanctified Jeremias 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 scandalised 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 might 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 honour before his dishonour, 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. They saw two suns; one in the sky, as usual, and one unusually; one visible in the firmament and lighting the world, and one, his face, visible to them alone. His garments white as light showed that the glory of his divinity flooded from his whole body, and his light shone from all his members. For his flesh did not shine with splendour from without, like Moses, but the glory of his divinity flooded from him. His light dawned and was drawn together in him. Nor did depart somewhere else and leave him, because it did come from another place and adorn him, nor was it for his use. And he did not display the whole depth of his glory, but only as much as the limits of their eyes could encompass.
‘And there appeared to them Moses and Elias talking with him’. And the words that they said to him were such as these: they were thanking him that their words and those of all their fellow Prophets had been fulfilled by his coming. They offered him worship for the salvation which he had wrought for the world for the human race; and that he had fulfilled in reality the mystery they had only sketched. There was joy for the Prophets and the Apostles by this ascent of the mountain. The Prophets rejoiced when they saw his humanity, which they had not known. The Apostles also rejoiced when they saw the glory of his divinity, which they had not known, and heard the voice of the Father bearing witness to his Son; and through this they recognised his incarnation, which was concealed from them. And the witness of the three was sealed by the Father’s voice and by Moses and Elias, who stood by him like servants, and they looked to one another: the Prophets to the Apostles and the Apostles to the Prophets. There the authors of the old covenant saw the authors of the new. Holy Moses saw Simon the sanctified; the steward of the Father saw the administrator of the Son. The former divided the sea for the people to walk in the middle of the waves; the latter raised a tent for the building of the Church. The virgin of the old covenant saw the virgin of the new: the one who mounted on the chariot of fire and the one who leaned on the breast of the flame [Elias and John]. And the mountain became a type of the Church, and on it Jesus united the two covenants, which the Church received, and made known to us that he is the giver of the two. The one received his mysteries; the other revealed the glory of his works.
St Ephrem the Syrian