In Matthew's Gospel, the story of Jesus walking on water morphs into a story of Peter walking on, then sinking into, the same water. It begins as a statement about Jesus' authority; for Jesus' contemporaries had learned from scripture that such mastery over the waters is God's accomplishment. When Peter tells Jesus to call him, too, onto the lake, the story transitions into an illustration of what it looks like when people express faith in Jesus.
Whatever the origins of this story and however it might or might not relate to a predawn experience Jesus' friends had on the volatile Sea of Galilee, the story prefers to press other questions. It serves up food for thought, mostly about who Jesus was and how he lives in us, but also about the nature of faith. Over the centuries this passage has fed Christians' allegorical reflections on what it means to walk faithfully in fearful circumstance. Remember that before we can walk in faith, we have to get out of the boat.