It’s recorded in the Gospels (e.g. Luke 9:28-36) and in 2 Peter 1:16-18.
For we did not follow cleverly devised myths when we made known to you the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty. For when he received honor and glory from God the Father, and the voice was borne to him by the Majestic Glory, “This is my beloved Son, with whom I am well pleased,” we ourselves heard this very voice
borne from heaven, for we were with him on the holy mountain. And we have the prophetic word more fully confirmed, to which you will do well to pay attention as to a lamp shining in a dark place, until the day dawns and the morning star rises in your hearts…
This icon is from the Retreat house where I began my sabbatical, Emery House (SSJE.org). All icons of the Transfiguration draw attention to “the uncreated light” of Christ. An ancient Orthodox hymn summarizes the great significance for understanding Christ and his mission…
On the Mountain You were Transfigured, O Christ God,
And Your disciples beheld Your glory as far as they could see it; So that when they would behold You crucified, they would understand that Your suffering was voluntary,
And would proclaim to the world,
That You are truly the Radiance of the Father!
Not only did this event foretell Christ’s atoning death, it also looks forward to the restoration of all things. Many of the Church Fathers said that the coming again of Christ will mean the whole universe will be like the burning bush seen by Moses: “radiant with the fire of God’s holiness, but not consumed.” (David B. Hart’s preface in The Uncreated Light)
Take some time to read the Gospel account and reflect on Christ’s Transfiguration and your own transformation into His likeness!