It is quite possible to overemphasize the newness and strangeness of what the disciples saw on Mt. Tabor. As an example of this overemphasis of the astonishment factor, which leaves this event more perplexing than it needs to be, some of the Greek fathers of the church, beginning with Irenaeus, tended to let the glory of this revelation blind them to its message about human nature. After all, the disciples saw that day their own destiny as well as the essential reality of Jesus Christ. Far from being an event of such otherworldly significance that the disciples should not even have been there, no moment in the Gospels is more plainly practical in its implications for how we should think about the relationship of God to matter. What the disciples saw at the transfiguration is the light that blinded Paul at his conversion and the flame that amazed Moses because it did not consume the burning bush. It is the “light that shines into the darkness” but also “the light of men” (John 1:3, 4). The transfiguration revealed not only who Jesus is but also what we are meant to be.
When the glory of God is emphasized in the transfiguration, it is too frequently interpreted as an occasion of a realized eschatology, as if God is cutting away the human medium of revelation and showing the disciples the divine substance in the entirety of its entire naked splendor. Nothing could be further from the truth. The incarnation is not just the medium but also the substance of the transfiguration. Jesus is showing us that just as his flesh is the form that God has given him and has thus made one with the divine, so too our flesh will one day be made one with his. Jesus Christ is unique but not exclusively so. His uniqueness, that is, serves a purpose. He is the one in whom all the saved shall find their lasting identity.
Stephen H. Webb, Jesus Christ, Eternal God: Heavenly Flesh and the Metaphysics of Matter (New York: Oxford University Press, 2012), pp. 162–163, 163–164