An apocryphal book lost to time.
Jude 1:9 - 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.”
Origen mentioned The Assumption of Moses was extant in his time and contained this account between Michael and the devil and he supposed this is the source of this verse.