What did Peter, James and John see on the Mount of Transfiguration? During a Bible discussion for seekers last week, one of them asked a question that led me to ponder this questions.

As I understand it, the body of Moses (not Elijah since he never died) should still have been in the grave at the time of the Transfiguration of Jesus--and would be pretty decomposed at that point.  However, his spirit (and probably souls) would have been in Paradise at that time--still separated from his body until the resurrection at the last day.


  And after six days Jesus took with him Peter and James, and John his
  brother, and led them up a high mountain by themselves. 2 And he was
  transfigured before them, and his face shone like the sun, and his
  clothes became white as light. 3 And behold, there appeared to them
  Moses and Elijah, talking with him.   Matthew 17:1-3 ESV


If that is true, then what exactly did Peter, James and John see on the Mount of Transfiguration?  Did they see the spirit of Moses?  Can our spirits be seen with physical eyes?  Were the disciples perhaps allowed to see spiritual things as Elisha appears to have done in 2 Kings 6?  


  When the servant of the man of God rose early in the morning and went
  out, behold, an army with horses and chariots was all around the city.
  And the servant said, “Alas, my master! What shall we do?” He said,
  “Do not be afraid, for those who are with us are more than those who
  are with them.” Then Elisha prayed and said, “O Lord, please open
  his eyes that he may see.” So the Lord opened the eyes of the young
  man, and he saw, and behold, the mountain was full of horses and
  chariots of fire all around Elisha.  2 Kings 6:15-17 ESV


As a side note, the rich man and Lazarus presumably "saw" each other as well.

I'm looking for the Protestant understanding of this.
In Jude 9, we read:


  But Michael the archangel, when he disputed with the devil and argued about the body of Moses, did not dare pronounce against him a railing judgment, but said, “ The Lord rebuke you!”


This is often taught as the body of Moses was taken into heaven.

We also know that Elijah ascended in a fiery chariot in a whirlwind:


  And as they still went on and talked, behold, a chariot of fire and horses of fire separated the two of them. And Elijah went up by a whirlwind into heaven


This would mean that the bodies of those mean would have been kept in heaven, so it could very well be that the two men were actually physically present.