Jesus has just been talking to the people and his disciples about following him. Six days later, Jesus goes with three of his disciples up a mountain where his appearance changes, so he looks as he will one day in the kingdom of God.
The kingdom of God coming represents God showing himself as king. AT: "God show himself with great power as king" (See: [[rc://en/ta/man/translate/figs-metonymy]])
The author uses the reflexive pronoun "themselves" here to emphasize that they were alone and that only Jesus, Peter, James, and John went up the mountain. (See: [[rc://en/ta/man/translate/figs-rpronouns]])
# he was transfigured
This can be stated in active form. AT: "he appeared very different" (See: [[rc://en/ta/man/translate/figs-activepassive]])
# before them
"in front of them"
# radiantly brilliant
"shining" or "glowing." Jesus' garments were so white they were emitting or putting out light.
# extremely
"very, very"
# whiter than any bleacher on earth could bleach them
Bleaching describes the process of making natural white wool even whiter by using chemicals like bleach or ammonia. AT: "whiter than any person on earth could whiten them"