Mark 9

And Jesus said to them, Truly and solemnly I say to you, there are some standing here who will in no way taste death before they see the kingdom of God come in [its] power.
2 Six days after this, Jesus took with Him Peter and James and John and led them up on a high mountain apart by themselves. And He was transfigured before them and became resplendent with divine brightness.
3 And His garments became glistening, intensely white, as no fuller (cloth dresser, launderer) on earth could bleach them.
4 And Elijah appeared [there] to them, accompanied by Moses, and they were [a]holding [a protracted] conversation with Jesus.
Mark 9:1-4 AMPC