What did Jude mean about not daring to bring a Slanderous Accusation against the Devil?

Let’s read the passage in question:

In the very same way, on the strength of their dreams these ungodly people pollute their own bodies, reject authority and heap abuse on celestial beings. ⁹ But even the archangel Michael, when he was disputing with the devil about the body of Moses, did not himself dare to condemn him for slander but said, “The Lord rebuke you!” ¹⁰ Yet these people slander whatever they do not understand, and the very things they do understand by instinct—as irrational animals do—will destroy them.

Jude 1:8-10

The subject of the passage is established in verse 4: “godless men who change the grace of our God into a license for immorality and deny Jesus Christ our sovereign and Lord.” That is, they deny Christ through their unrepentant immoral actions; see Titus 1:16.

This refers to libertines, aka lawless, licentious, hedonistic people who, in this particular case, put on the airs of being “Christian” in order to slip in amongst believers and teach their licentious false doctrines.

As far as “heaping abuse on celestial beings” goes (verse 8), these hedonists “reject authority” in general, as did the sinning angels (v. 6), both natural and spiritual authorities, thus rejecting the authority of the Holy Scriptures and denying Christ (v. 4). Apparently they ridiculed spiritual powers that were beyond their comprehension, likely because libertines (hedonists) are naturally oriented to the physical realm, as opposed to being genuinely spiritual.

In confronting and contending with the devil in a dispute over Moses’ body, Michael the archangel did not personally condemn such a powerful fallen angel for his sins — he’s The Slanderer, of course — but instead deferred to the ultimate, sovereign power of God following the supreme example of the Angel of the LORD in Zechariah 3:1-2. This illustrates how believers are to deal with Satan & demons: Utilize the LORD’s intervening power against them, e.g. “In the name of Jesus Christ I cast you out!” In other words, instead of cursing the darkness, simply turn on the lights.

This doesn’t mean that a believer can’t, for instance, refer to Satan as a “loser” in a sermon/article/book or describe him as “morally filthy” because both are true — Satan is the Ultimate Loser who’s morally filthy — and thus pointing this out is not slander. Christ called the devil & his foul minions “snakes and scorpions” (Luke 10:19). At the same time, we should be careful about copping a cocky, flippant air when it comes to celestial beings, fallen or not.

Jude 1:3-10 is paralleled in 2 Peter 2 for those interested.

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Demons Vs. Jesus Christ — No Contest!

Armor & Weaponry of God

Spiritual Warfare — Do You know What You’re Fighting For?

Is Name-Calling Ever Appropriate?