Having established that his readers were in danger of being led astray by false teachers, in verses 5-7 Jude then proceeded to give three illustrations from the Old Testament of how God brought judgment upon those who oppose His truth. And so by reminding us of the people of Israel who died in the desert, the angels who left heaven to join the rebellion against the Lord and the citizens of Sodom and Gomorrah who lived lives of sexual immorality, Jude gave a strong warning to his readers. These lessons from the Old Testament were written for us and should be noted well. God will not be mocked. His Word teaches that ‘a man reaps what he sows’.