Jesus had just been talking to the people and his disciples about following him.

## he was transfigured ##

"he changed into another form" or "he appeared very different" (UDB)

## radiantly brilliant ##

"exceedingly white"

## bleacher on earth could bleach them ##

"Bleach" is a chemical used to remove stains from clothes and to make them white. A "bleacher" is someone who does the stain removal.