Mark 9:1-4

And he said to them, “Truly I tell you, some who are standing here will not taste death before they see that the kingdom of God has come with power.” After six days Jesus took Peter, James and John with him and led them up a high mountain, where they were all alone. There he was transfigured before them. His clothes became dazzling white, whiter than anyone in the world could bleach them. And there appeared before them Elijah and Moses, who were talking with Jesus.