1) No, seems it "came out of the blue" literally..Checkpoint wrote: The Transfiguration of Jesus is described in each of the three synoptic Gospels.
These passages are Matthew 17:1-9; Mark 9:2-9; and Luke 9:28-36.
Peter writes about it in 2 Peter 1:16-18.
Scriptures that raise a number of questions for debate, such as:
1) Did Jesus tell anyone in advance this would happen?
2) Why did it happen?
3) Were Moses and Elijah literally there?
4) Why did Moses and Elijah appear and then disappear?
5) Does what God said have any particular significance?
6) Why did Jesus say to tell no one about it until after his resurrection?
2) Moses represents the Law, Elijah the Prophets. God was seemingly telling the apostles present, (and the Gospel Evangelists, their readership) that Jesus and his message are even more important than the Law and the Prophets.
3) Not sure it's important if Moses and Elijah (or their spirits) were literally there. It was a vision designed to convey a message.
4) As opposed to appearing, then staying on?
5) See answer #2
6) Good and thought provoking question.