I've always liked the Gospel story of the Transfiguration. I like that the apostles fall asleep while waiting for Jesus to finish praying - it makes them seem very human. I like that Jesus was conversing with Moses and Elijah - the way that the Old and the New Testaments fit together and form a whole. I like that Peter's first inclination upon awaking and seeing the sight is to build three monuments (somehow I definitely think that if it happened in this day and age a monument would be built.) I like that God speaks to them from a cloud.
I've always had a question.
See, there was no photography back in the first century - or beyond, when Moses and Elijah would have been alive. And the Jews did not allow graven images - so it is unlikely there would have been any paintings or statues of the two men. So - what I've always wondered - is how did Peter, James and John immediately know that they were Moses and Elijah. Why didn't they think - "who are those old guys up there with Jesus? They didn't come up the mountain with us. "
I suppose the logical answer is that God granted them the knowledge.
May God grant us the knowledge we need in our own lives.