The Transfiguration of Christ (Matthew 17:1-9) is not so much that Christ was somehow changed, but that the apostles themselves were changed enabling them to see Christ as is always is. The limits of seeing only with one’s eyes was lifted in that moment and the Apostles saw with the eyes of their heart who Jesus is.
“He was transfigured, then: not taking on what he was not, nor being changed to what he was not, but making what he was visible to his own disciples, opening their eyes and enabling them, who had been blind, to see. This is what the phrase means, “He was transfigured before their faces”; he remained exactly the same as he was, but appeared in a way beyond the way he had appeared before, and in that appearance seemed different to his disciples.” (St John of Damascus, Light on the Mountain, p. 221)
“To speak of a ‘transfiguration of creation’ in such cases is clearly to speak from the viewpoint of human experience. Just as the transfigured Christ does not change in himself, but simply allows his disciples to briefly perceive him as he is, so it is with creation’s praise of God: it becomes perceptible only when humans have ears to hear.” (Elizabeth Theokritoff, Living in God’s Creation, pp. 144-145)