What did these two talk to a tired and dread-filled Jesus about? Of the three synoptic gospels (Matthew, Mark, and Luke), only Luke tells us that Moses and Elijah talked with Jesus about his exodus from Jerusalem. They told him, I imagine, to view his journey to Jerusalem as an exodus from death to life, like the Red Sea passage, and to view his end in the same way. They reassured him of the glory. They offered him encouragement. And then, our story says, they went away and "Jesus was found alone." If I had been in Jesus' place, I would not have wanted them to go. I would have wished they would stay and help me in the exodus that lay before me! Like Peter, I might have babbled about building them booths or tabernacles to stay with me forever up on the mountain.
In the throes of a lengthy labor with my first child, I remember clinging to the hand of a kindly nurse, who was trying to extricate herself from my grasp. "Give me back my hand now, honey," she said, kindly but firmly. "My shift is over now. I've gotta go home." I let go of her hand, reluctantly. She smiled at me and said, with that wonderfully practical manner that nurses have, "If one of us has to leave, it better be me. Because you're the only one who can have this baby."
So the two prophets say to Jesus, "Our shift is over. There's a job that only you can do."
Then a Cloud overshadows Jesus and the others, the same Cloud that stood at the door of Moses' tent to mark the Presence of God (Shekinah). The Cloud lifts, and Jesus is left alone. With a refreshed sense of his own identity, he is inspired by the suffering and glory of Moses and Elijah. Assured of God's presence in his own suffering and glory, he gestures to his disciples to fall in behind him and follow him down the mountain.