Luke’s account of the Transfiguration has several details that aren’t included in Mark’s version. This makes sense for a couple of reasons: first, Mark is in a hurry and details, unless absolutely necessary, are superfluous; second, Mark is the first gospel written, so the story is logically going to grow as time passes. One of the details that Mark and Matthew both gloss over, but Luke decides to include is the topic of conversation between Jesus, Moses, and Elijah.
“They appeared in glory and were speaking of his departure, which he was about to accomplish at Jerusalem.”
If it weren’t for the second half of that sentence, having this come on the heels of Jesus being rejected at Nazareth, one could think that Moses and Elijah were giving Jesus a hard time for his almost being thrown off a cliff in his hometown. There, Jesus walked to safety “through the midst of them,” not unlike Moses and the people of Israel walking to safety from Pharaoh’s army between the Red Sea’s walls of water on their left and right. Alas, that isn’t the exodus they were talking about.
Instead, Moses, Elijah, and Jesus were talking about the new Exodus, God’s saving work for the whole world, which Jesus would accomplish in Jerusalem. This Exodus wouldn’t involve blood on the door posts of those who would be saved, but instead, the blood on the cross would serve as the saving mark for all of creation. The people wouldn’t flee from the evils of one place for the promise of another, but instead, the promise of God’s kingdom would find a way to overcome the evils of this world. The Exodus of Jesus will bring us to a promised land that doesn’t inhabit time and space, but rather is available not matter who we are, where we live, or when we accept God’s grace.
The conversation about the Exodus is good news, but the disciples are unable to hear it that way. They’re weighed down with sleep: simultaneously confused and amazed by what they are seeing. It’ll take Jesus dying on a cross, rising to life again, ascending into heaven, and ten days after that before the Spirit will come and begin to make sense of it all. In the meantime, like the people of Israel in the desert, the disciples follow Jesus, unsure of where they are going.