Why was the Angel Michael fighting the Devil for Moses' body? I get this from the book of Jude. I know the meaning of the chapter as a whole it's just that this verse stuck out. Does anyone have a clue on this event? Here is the verse for reference.


  Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, durst not bring against him a railing accusation, but said, The Lord rebuke thee. [Jde 1:9 KJV]
It appears that the author of Jude was quoting from an apocryphal Jewish scroll known as the Assumption of Moses.

Origen stated in De principiis, III,2,1:


  "We have now to notice, agreeably to the statements of Scripture, how
  the opposing powers, or the devil himself, contends with the human
  race, inciting and instigating men to sin.  And in the first place, in
  the book of Genesis, the serpent is described as having seduced
  Eve; regarding whom, in the work entitled The Ascension of Moses
  (a little treatise, of which the Apostle Jude makes mention in his
  Epistle), the archangel Michael, when disputing with the devil
  regarding the body of Moses, says ..."


A fragment of the Assumption of Moses has been discovered, but it does not include the account of Michael and the devil disputing over the body of Moses, which means that we can not say how this account played out, or why the author of Jude chose to mention it, apart from its apparent support for Jude's theology.