See an account of the transfiguration in Matthew 17:1-13, and Mark 9:2-13.
The fashion - The “appearance.”
Glistering - Shining like lightning - of a bright, dazzling whiteness. As Mark says, “more white than any fuller could make it.”
In glory - Of a glorious appearance. Of an appearance like that which the saints have in heaven.
His decease - literally, his “exit” or “departure.” The word translated here “decease” - that is, exit, or “going out” - is elsewhere used to denote death. See 2 Peter 1:15. Death is a departure or going out from this life. In “this” word there may be an allusion to the “departure” of the children of Israel from Egypt. As that was going out from “bondage,” pain, and humiliation, so death, to a saint, is but going forth from a land of captivity and thraldom to one of plenty and freedom; to the land of promise, the Canaan in the skies.
He should accomplish - Which was about to take place.
Heavy with sleep - Borne down with sleep - oppressed, overcome with sleep. It may seem remarkable that they should fall asleep on such an occasion; but we are to bear in mind that this may have been in the night, and that they were weary with the toils of the day. Besides, they did not “fall asleep” while the transfiguration lasted. While Jesus was praying, or perhaps after he closed, they fell asleep. “While” they were sleeping his countenance was changed, and Moses and Elias appeared. The first that “they” saw of it was after they awoke, having been probably awakened by the shining of the light around them.
Jesus was found alone - That is, the two men had left him. In respect to “them” he was alone.