What is the deal with Moses’ body (Jude 9)?
But when the archangel Michael, contending with the devil, was disputing about the body of Moses, he did not presume to pronounce a blasphemous judgment, but said, "The Lord rebuke you."
What is the dispute about Moses' body? We have to go back to Deuteronomy to get the details surrounding Moses' death.
Deuteronomy 34:5-6 says:
So Moses the servant of the LORD died there in the land of Moab, according to the word of the LORD, and he buried him in the valley in the land of Moab opposite Beth-peor; but no one knows the place of his burial to this day.
Notice from the text: God Himself buried Moses. And apparently in the heavenly/spiritual realm, there was a dispute between Michael the angel and Satan the fallen angel over Moses' body.
God buried Moses so no one knew where his body was. And we know if God wanted it secret, Satan would want to keep Moses' body around publicly. Why would Satan want that? Israel had a tendency to focus on the past, inappropriately. For example, look at Numbers 11:4-6. "Oh, we wish we were slaves again! The food in Egypt was sooooo good! Now we are in the middle of the wilderness, suffering!"
If Moses' body were kept around, I believe 100% Israel would have started worshiping it. Sound crazy? Well, remember the golden calf they worshiped while Moses was on conference with God? They had that tendency. Further, they would have been tempted to be stuck in the past, the "good ol days of Moses" instead of moving on under Joshua like God intended.
So Satan thought keeping a stumbling block around Israel by keeping Moses' body around would surely get God's people off course. God sent Michael to take care of it, according to Jude 9. And Moses' supernatural burial remained a mystery, to Israel's benefit.