I like pointing out that our missals tell us today’s Gospel starts in Luke Chapter Nine , verse 28b. It leaves off the first half of verse 28. That half verse tells us “About eight days after this . . .”
That first half of Luke verse 28 was making the point that today’s incident was brought on by what happened eight days before. That was when Jesus had saddened both the disciples and himself by saying their happy days were drawing to a close. He told them he would be handed over to foreigners and put to death. He followed up that with the dire warning that his disciples too would have to take up crosses.
Those two sad predictions might have sunk in a little with Peter, James and John; so, a week later, when Jesus, in need of comfort from the Father, climbed a mountain, he brought Peter, James and John along for their share of heavenly assurance.
On the mountain they had a heavenly experience that was beyond words. The story Luke laid before us probably isn’t factual, but it doesn’t even come close to giving us a feel for the touch with heaven they experienced.
The disciples had fallen asleep as Jesus went on praying. Then they awoke to seeing the bottom of heaven stretching down like a trampoline. It stretched down just far enough to take Jesus up in it. With that, he was changed into a heavenly being. He appeared glorified.
The Jews had a belief that just two mortals had made it to heaven. They were Moses and Elijah. Moses along with the whole of his grave from opposite Beth Peor had been taken up to heaven, and Elijah had been taken up in a fiery chariot. Those two came over to chat with Jesus. Luke tells us they talked about the end of Jesus’ mission.
Then, as Peter tells us in his Second Letter, they heard the Father calling Jesus his Son. God staged that foretaste of the heavenly reward to let Jesus and the disciples see that they would be rewarded for their sufferings. It was also staged to give us hope.