Mark 9:10

And they kept that saying with themselves, questioning one with another what the rising from the dead should mean.

Just as quickly as the miraculous appearance had begun, it also ended. The disciples, still half dazed, felt that the pall was lifted, and, looking about them, saw no one but Jesus alone with them. Moses and Elijah had been returned to the place of eternal happiness in the same wonderful manner as they had been brought down to the mountain. Jesus, their Master, now was with them again in His usual form and dress, with no evidence of the glory which had just shone through Him. His reassuring words and touch brought them back fully to their senses. While they were then descending from the mountain together, He gave them the earnest charge to transmit the account of what they had seen to no one until after the resurrection of the Son of Man. The people had an altogether wrong idea as to the work and mission of the Messiah, and the news of this miraculous appearance would only have strengthened this false conception. But at that time, when His. death would have removed and disproved all wrong beliefs and hopes in an earthly Messiah, with an earthly kingdom, and especially after He would have risen from the dead, then this revelation should be part of their preaching, they should not hesitate about proclaiming the full truth about the transfiguration. The three disciples accepted this charge in the proper spirit of meekness and obedience; they kept their secret until the time that Jesus had indicated, even from the other disciples. In the meantime, however, they discussed the question among themselves, how that was to be understood concerning the rising from the dead. Not that they did not know that there would be a resurrection of the dead on the last day. This doctrine was known and believed by all the Jews, the only ones dissenting being the sect of the Sadducees. The difficulty for them lay in this, both when He should arise from the dead, as some manuscripts have it, and how this would be done. Christ's one announcement concerning His Passion, death, and resurrection had not yet entered into their heart and understanding. What express and particular resurrection of the dead the Lord was referring to for Himself was a mystery to them. Thus earnest Christians will find many points in Scriptures and in the sayings of Jesus that are a mystery to them; they do not understand in what sense they are to be understood and applied in individual instances; but careful searching of the Word will open the eyes, under the guidance of the Spirit.