You go into the movie theatre, find a seat that's suitable, clamber over some poor innocent slumbering in the aisle seat, taking pains not to step on toes or lose your balance. You find a place for your coat, sit down, and get ready to watch the movie. The house lights dim; the speakers crackle as the dust and scratches on the soundtrack are translated into static, and an image appears on the screen. It is not the film you came to see. It is the preview of coming attractions, a brief glimpse of the highlights of a film opening soon. The moviemakers and theater owners hope the preview will pique your interest enough to make you want to come back and see the whole film.

On the Mount of the Transfiguration, Peter, James and John, the inner circle of Jesus' disciples, were given a preview …