Mark 9:2-4

2Six days after that, Jesus asked Peter, James and John to go with him. Jesus led them up a high mountain, where they were alone together. Peter, James and John saw Jesus change in front of them.

3His clothes became very white; they were shining. They were a brighter white than anyone on earth could wash them.

4Then Elijah and Moses appeared in front of the three disciples. Elijah and Moses were talking with Jesus.