2 Peter 1:16-19; Psalm 96(97):1-2,5-6,9; Mark 9:2-10
One of the more enigmatic events in the Bible, the transfiguration is quite unlike any other. The Old Testament does not prepare us for it, and none of the surviving epistles mention it. It occurs in Mark's gospel inserted between his missionary accounts (the sermons etc) and the passion. None of Jesus's authenticity depends upon the event, and it does not complete any prophetic words, so why is it included in the bible at all? In studying the bible we need to have the idea that every word is precious and has a meaning.
If the transfiguration was removed from the bible we probably would not miss it, but it is there, and so we should not ignore it. The fact that it was written down suggests that it did happen - why on earth would anyone make it up? So why did it happen?
Jesus was very much a human - born of a woman, he ate, laughed, told stories, worked (probably as an apprentice to Joseph the Carpenter) and if you touched him, he would feel you, and you would feel him. But he also was God, and this event gives us a glimpse of what that might mean. What does Jesus do during the transfiguration? He talks with Elijah and Moses. They had both had visions of God on the holy mountain - and so are now seeing Jesus as God: the apostles and we ourselves are also meant to see him as God.
In Jesus God and Man, we from now onwards find our salvation.