+ Mt 17: 1-9
After six days Jesus took Peter, James, and John his brother, and led them up a high mountain by themselves.
And he was transfigured before them; his face shone like the sun and his clothes became white as light.
And behold, Moses and Elijah appeared to them, conversing with him.
Then Peter said to Jesus in reply, “Lord, it is good that we are here. If you wish, I will make three tents here, one for you, one for Moses, and one for Elijah.”
While he was still speaking, behold, a bright cloud cast a shadow over them, then from the cloud came a voice that said, “This is my beloved Son, with whom I am well pleased; listen to him.”
When the disciples heard this, they fell prostrate and were very much afraid.
But Jesus came and touched them, saying, “Rise, and do not be afraid.”
And when the disciples raised their eyes, they saw no one else but Jesus alone.
As they were coming down from the mountain, Jesus charged them, “Do not tell the vision to anyone until the Son of Man has been raised from the dead.”
The New American Bible
The Catechism of the Catholic Church
554 From the day Peter confessed that Jesus is the Christ, the Son of the living God, the Master “began to show his disciples that he must go to Jerusalem and suffer many things. . . and be killed, and on the third day be raised.” Peter scorns this prediction, nor do the others understand it any better than he. In this context the mysterious episode of Jesus’ Transfiguration takes place on a high mountain, before three witnesses chosen by himself: Peter, James and John. Jesus’ face and clothes become dazzling with light, and Moses and Elijah appear, speaking “of his departure, which he was to accomplish at Jerusalem”. A cloud covers him and a voice from heaven says: “This is my Son, my Chosen; listen to him!”