Mark 9 v1-6

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.’

² 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. ³ His clothes became dazzling white, whiter than anyone in the world could bleach them. ⁴ And there appeared before them Elijah and Moses, who were talking with Jesus.

⁵ Peter said to Jesus, ‘Rabbi, it is good for us to be here. Let us put up three shelters – one for you, one for Moses and one for Elijah.’ ⁶ (He did not know what to say, they were so frightened.)