And after six days Jesus took with him Peter and James and John his brother, and led them up a high mountain apart. And he was transfigured before them, and his face shone like the sun, and his garments became white as light.
According to the Catechism of the Catholic Church, “For a moment Jesus discloses his divine glory, confirming Peter's confession. He also reveals that he will have to go by the way of the cross at Jerusalem in order to ‘enter into his glory’ (Luke 24:26)” (CCC, 555).
While meditating on the Transfiguration, say one Our Father, ten Hail Mary’s, and a Glory Be (see "How to Pray the Rosary" if you are unfamiliar with any of these prayers).