What does Jude say false teachers ran greedily after?
Jude says false teachers ran greedily after the error of Balaam, which was done for reward. They had gone in the way of Cain, and they perished in the gainsaying of Korah. Balaam's error was thinking that if Israel sinned openly, God would curse them.
Les explains that Jude is describing false teachers who creep into the local church unawares, men ordained of old to condemnation, ungodly men who turn the grace of God into lasciviousness and deny the only Lord God, our Lord Jesus Christ. Jude then shows how these false teachers operate: they speak evil of things they know not. He pronounces woe because they have gone in the way of Cain, which was no faith, and ran greedily after the error of Balaam for reward. Les notes that this is the error of Balaam, the false prophet. Balaam thought that if he could get Israel to lose her separated position with Jehovah and get them to sin openly, then God would curse them. Les adds that Balaam succeeded, and that they also perished in the gainsaying of Korah, another Old Testament event.