And he went on to say, “I tell you, there are some here who will not die until they have seen the Kingdom of God come with power.”
Six days later Jesus took with him Peter, James, and John, and led them up a high mountain, where they were alone. As they looked on, a change came over Jesus, and his clothes became shining white — whiter than anyone in the world could wash them. Then the three disciples saw Elijah and Moses talking with Jesus. Peter spoke up and said to Jesus, “Teacher, how good it is that we are here! We will make three tents, one for you, one for Moses, and one for Elijah.” He and the others were so frightened that he did not know what to say.
Then a cloud appeared and covered them with its shadow, and a voice came from the cloud, “This is my own dear Son — listen to him!” They took a quick look round but did not see anyone else; only Jesus was with them.
As they came down the mountain, Jesus ordered them, “Don't tell anyone what you have seen, until the Son of Man has risen from death.”
They obeyed his order, but among themselves they started discussing the matter, “What does this ‘rising from death’ mean?” And they asked Jesus, “Why do the teachers of the Law say that Elijah has to come first?”
His answer was, “Elijah is indeed coming first in order to get everything ready. Yet why do the Scriptures say that the Son of Man will suffer much and be rejected? I tell you, however, that Elijah has already come and that people treated him just as they pleased, as the Scriptures say about him.”