These are very strong words!  Jude is leaving his readers in no doubt about the extreme danger posed by false teachers who have no respect for God’s Word, who believe themselves more powerful than angels and demons, and who have no moral restraint.  Although people like that appeal to the worst fleshly instincts, they were being tolerated in some churches.  So Jude emphasised the words of Jesus: “Watch out for false prophets. They come to you in sheep's clothing, but inwardly they are ferocious wolves.” (Matthew 7:15)

Jewish readers would have known a traditional story about the devil demanding to have the body of Moses, and not even the archangel Michael dared to use his own authority to rebuke Satan; instead, he left the fate of the Evil One in God’s hands (Deuteronomy 32:35).  Jude uses the story to demonstrate the stupidity of playing with spiritual fire.  In the same way the false teachers had no idea of the physical and social damage caused by immoral behaviour (Revelation 2:14-16).  Neither did they understand the spiritual danger of assuming God-like authority; nor did they realise that the wrath of God is upon those who practise and teach such things (2 Peter 2:13-22).

When truth has been abandoned, and people think that nobody can stand in their way, they become like animals that cannot understand the future (2 Peter 2:12). Understanding and wisdom comes from God, but when He is rejected they cannot see where they are or the consequences of their actions.

When people refuse to give glory to God, He removes the privilege of wise observation and blinds their eyes so that they stumble around in the dark (Jeremiah 13:16).  The Apostle Paul wrote, “Warn a divisive person once, and then warn them a second time. After that, have nothing to do with them.” (Titus 3:10)  That may seem harsh (some would even say un-Christian) but false teaching is a poison which will destroy God’s people.  So keep clear of it: personally, with your family and friends and in the church.