The Transfiguration of the Lord can sound embarrassingly magical. Jesus goes up onto a mountain and his clothes become dazzlingly white. Prophets appear and talk to him. And then it is all over and Jesus tells his disciples to say nothing.
We should hold on to the absurdity of the incident. There is simply no reason for all this to have happened. In particular, there is no reason to put it into a gospel – the evangelist makes no capital out of it, it is simply there.
And this is the strength of the Transfiguration as an historical incident. There is no reason for anyone to have invented it. It is not central to the Christian case. It is not used to win arguments. There is only one reason to put it into the Gospel, and that is because it happened. It is one of those cases of the evangelists writing things down without knowing why they were important, and their very puzzlement is what makes the story so convincing.
Why, then, did it happen? Surely so that we could see and understand that Jesus is at once one of the prophets and the one that was prophesied by them; and that he is God, and lives for all eternity in a blaze of dazzling and unapproachable light.
The true miracle of the Transfiguration is not the shining face or the white garments, but the fact that for the rest of the time Jesus hid his glory so well.