Jude refers to “Michael the archangel” disputing with the devil “about the body of Moses” Jude 1:9. He says Michael did not pronounce a reviling judgment but said, “The Lord rebuke you” Jude 1:9.
In Jude 1:8–11, Jude says the intruders behave like reckless dreamers: they stain their bodies, reject rightful rule, and insult heavenly beings. He contrasts them with Michael, who refuses to hurl abusive words even at the devil, instead appealing to the Lord’s rebuke. This unit continues Jude’s warning about people who slipped into the community and are twisting life and teaching from within (see the lead-up in Jude 1:4). After earlier examples of past judgments, Jude turns to the present behavior of “these” people and piles up accusations in quick strokes.
Jude 1:8–11 presents “these people” as dangerous insiders whose claims to spiritual insight (“dreaming”) produce three visible outcomes: moral corruption (“defile the flesh”), rejection of rightful rule (“despise authority”), and abusive speech aimed upward (“slander celestial beings”).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Jude 1:9, then read the surrounding section so the answer stays connected to the passage's flow.
9But Michael, the archangel, when contending with the devil and arguing about the body of Moses, dared not bring against him an abusive condemnation, but said, "May the Lord rebuke you!"