Jesus took the three disciples up a high mountain. Mountains were seen as places where one could come nearer to God. Moses had received the Ten Commandments on Mount Sinai (Exodus 20:1-17) and Elijah had met God on Mount Horeb (1 Kings 19:11-13). These two great leaders of the Old Covenant appeared in a vision with Jesus. It is as though Peter, James and John saw before them the whole history of salvation in miniature, which God brought about through the Jewish people: the law-giver Moses appeared with the prophet Elijah, with Jesus the redeemer as central figure.
Though Jesus was their leader and teacher they would have seen him as a human being like themselves. Now he was revealed in his true glory. It was a moment they wanted to hold on to for ever; but it was transitory. Nevertheless it was an event that would sustain them when the Lord was taken from them. It would have helped them to see more clearly God’s plan for humanity in the darkness of Good Friday.