Woe to them! For they walked in the way of Cain and abandoned themselves for the sake of gain to Balaam's error and perished in Korah's rebellion.
Jude is a book written to the early church to warn them about these type of teachers:
Jude 1:4 (ESV)
For certain people have crept in unnoticed who long ago were designated for this condemnation, ungodly people, who pervert the grace of our God into sensuality and deny our only Master and Lord, Jesus Christ.
These teachers, apparently, did not follow the sound doctrine laid out by the Apostles, but rather followed and taught their own visions and dreams:
Jude 1:8 (ESV)
Yet in like manner these people also, relying on their dreams, defile the flesh, reject authority, and blaspheme the glorious ones.
Jude is very similar to 2 Peter:
2 Peter 2:1-3 (ESV)
But false prophets also arose among the people, just as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Master who bought them, bringing upon themselves swift destruction. And many will follow their sensuality, and because of them the way of truth will be blasphemed. And in their greed they will exploit you with false words. Their condemnation from long ago is not idle, and their destruction is not asleep.
These false teachers, writes Jude, walk in the way of “Cain” and in the way of “Balaam” and in the way of “Korah.” In each of these illustrations Jude is telling us that these false teachers were about themselves and not about Christ and others. Cain slew his brother Abel because his own works were veil but his brother’s works were righteous:
1 John 3:12 (ESV)
We should not be like Cain, who was of the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil and his brother's righteous.
Balaam wanted money to curse Israel for King Balak (2 Peter 2:15). The Korahites wanted the same authority as Moses (Numbers 16:1-3, 31-35).
Those who come into churches for their own gain and their own promotion, using their own words of “wisdom” will undoubtedly bring destruction onto the church and themselves. Jude is warning us against false teachers who have these motives and these plans.