Six examples of the ungodly are given here: three groups and then three individuals.
Of all the men from twenty years old and above, within the nation of Israel who were rescued by God out of Egypt, only two men were allowed to live sufficiently long to enter the promised land: Joshua and Caleb. All the others were destroyed, primarily as a punishment for unbelief (Numbers 14:27-37, Hebrews 3:19). They refused to enter the Promised Land, when they discovered there were fortified cities and big powerful warriors in the land. They didn't believe the LORD was able to give them victory, in spite of all the evidence they had already received of His presence and support.
God had originally given them a promise with two parts to it: "I will take you out of Egypt and I will bring you into the land." They had been taken out of Egypt, miraculously, but said they preferred to stay in the wilderness rather than enter the land and trust God to deliver it into their hands. God therefore left them to wander in the wilderness for thirty-eight more years until all that generation had died, with the exception of Caleb and Joshua. They had used their children as an excuse for not going into the land; so God said, 'But your little ones, whom you said would be victims, I will bring in, and they shall know the land which you have despised' (Numbers 14:31).
The sin of unbelief gives rise to other sins: for example, because of their unbelief, some of them became idolaters, others committed sexual immorality, some tempted God and others complained of Him (1 Corinthians 10:5-11). "
Although they were once pure, holy, and living in God's presence, some, like Lucifer, were not satisfied with this, gave in to pride and ambition and joined him to rebel against God (2 Peter 2:4).
Very little is revealed to us about this in the Bible, as it does not concern our own relationship with God. These angels are bound in chains, awaiting the judgment of the "great day", which is the day of the Lord (Isaiah 2:9-22). As the final judgment upon Satan occurs after the thousand years, and preceding the final judgment (Revelation 20:10), it is seems reasonable to conclude that other fallen angels are judged with him (2 Peter 2:4).
Believers are associated with Christ in this judgment (1Corinthians 6:3).
God destroyed these cities because the people living in them defiled their flesh. Defiling the flesh is a consequence of ungodliness: those who refuse to believe the evidence of God's existence and to glorify Him become fools, changing the glory of the incorruptible God for an image of corruptible man. God gives them up to vile passions, women exchange the natural use for what is against nature, and men leave the natural use of the woman in order to burn in their lust for one another (Romans 1:21-27).
Those people in the "cities of the plain" were given over to what is called homosexuality today. In God's sight it is gross immorality and the vilest sin of all. The fact that God has judged men in the past for such a sin of sensuality ought to be a warning to people today.
Many people don't want to believe that God sentences people to "eternal fire" for rejecting him. But this is clearly taught in Scripture. Sinners who don't seek forgiveness from God will face eternal separation from him. Jude gives this warning to all who rebel against, ignore, or reject God.
The ungodly men who secretly slip into the church have four characteristics, in addition to turning the grace of God into lasciviousness and denying the Lord Jesus Christ, as previously mentioned :
They are dreamers: they have false ideals and get into the church with a view to mould the church of the Lord Jesus Christ into their own model. They do not realise that the church belongs to Him and that they are proceeding wickedly in what they do.
They defile the flesh. "All things are pure to the pure; but to the defiled and unbelieving nothing is pure; but both their mind and their conscience are defiled" (Titus 1:15). They engage in base and abnormal immorality like the cities in the plain. Many churches today, led by such ministers, have voiced their approval of homosexuality, for example.
They reject authority. They negate the full authority of the Word of God, and do not submit to the authority and discipline of the overseers in the church they have entered. They consider themselves free to do as they please, in or out of the church.
They speak evil of dignitaries. As they reject divinely appointed authority, they also have little regard for the ordinance of men, those in authority for the punishment of evildoers and for the praise of those who do good, to whom we are required to submit for the Lord's sake (1 Peter 2:13,14). The seriousness of this offence is pointed out by reference to the attitude of the archangel Michael towards satan, when he disputed about the body of Moses. There is no mention of the circumstances in the Scriptures, so it is not for us to speculate about it. Jude was inspired by the Holy Spirit to write only what we find here, to serve as an illustration of respect towards dignitaries. Michael is the only archangel identified by a name in the Bible, which means "who is like God?", and is called one of the chief princes in the prophecy of Daniel (10:13,20, 12:1). The devil is a cherub, apparently the highest creature that God created (Ezekiel 28:14). But evil was found in him, when driven by pride he rebelled against God. In spite of this, the great prince Michael didn't charge him with blasphemy, when he tried to prevent Michael from obeying God's instructions, but simply said, "The Lord rebuke you!"
The ungodly do not understand "invisible things", or spiritual things, and speak evil of them. All that they understand is what they can handle and what they can see, the material things. They are like brute beasts which live by instinct, without comprehension or understanding, but they corrupt themselves with these material things.
These are the characteristics of the ungodly men who come into the churches, and they are dangerous because of the way they come in, like the Trojan horse. What an entire army of mighty men could not do from the outside in ten years, a few soldiers did from the inside. In the same way, many churches have been corrupted over the ages from the inside, by ungodly men coming in through the side door.
Of these ungodly men Jude now says "Woe unto them!" The word for "woe" is the Greek word ouai. The very pronunciation of this word is a wail "Ouai, ouai!" It denotes a wail of grief or of denunciation. Here it is more a wail of denunciation, but it is both.
Three more examples are now given, three individuals.
He thought that he could come his own way to God, rejecting redemption by blood. Cain did not come to God by faith, but sought to do so by his own works. He believed in religion and God, but he wanted to do it his own way, not God's way (Hebrews 11:4).
Excessive indulgence in covetousness was the error of Balaam. He was a hired preacher, and wanted to make his fortune with his apparently God-given gift of prophecy. There are many different things which may put a man in the way of Balaam: avidity for prominence, for popularity, for fame, for applause, for position, etc.
Korah contradicted the authority of Moses and rebelled against him. He intruded into the office of the priests, and he was punished with death because, in so doing, he really rebelled against God (Numbers 16).
5 But I want to remind you, though you once knew this, that the Lord, having saved the people out of the land of Egypt, afterward destroyed those who did not believe.
6 And the angels who did not keep their proper domain, but left their own abode, He has reserved in everlasting chains under darkness for the judgement of the great day;
7 as Sodom and Gomorrah, and the cities around them in a similar manner to these, having given themselves over to sexual immorality and gone after strange flesh, are set forth as an example, suffering the vengeance of eternal fire.
8 Likewise also these dreamers defile the flesh, reject authority, and speak evil of dignitaries.
9 Yet Michael the archangel, in contending with the devil, when he disputed about the body of Moses, dared not bring against him a reviling accusation, but said, "The Lord rebuke you!"
10 But these speak evil of whatever they do not know; and whatever they know naturally, like brute beasts, in these things they corrupt themselves.
11 Woe to them! For they have gone in the way of Cain, have run greedily in the error of Balaam for profit, and perished in the rebellion of Korah.