Jude is another brother of Jesus. He also hung out with the apostle Peter after the Lord’s final physical departure from earth. His letter diagnoses and confronts the unseen spiritual disease in the early church.
“For certain men whose condemnation was written about long ago have secretly slipped in among you. They are godless men, who changed the grace of our God into a license for immorality and deny Jesus Christ our only Sovereign and Lord. Though you already know all this, I want to remind you that the Lord delivered His people out of Egypt, but later destroyed those who did not believe. And the angels who did not keep their positions of authority but abandoned their own home —these He has kept in darkness, bound with everlasting chains for judgment on the great Day.” (Jude 1:6)
Jude calls out to all believers to remember what the apostles of our Lord Jesus Christ foretold. “In the last times there will be scoffers who will follow their own ungodly desires. These are the men who divide you, who follow mere natural instincts and do not have the Spirit. But, you dear friends build yourselves up in your most holy faith and pray in the Holy Spirit. Keep yourselves in God’s love as you wait for the mercy of our Lord Jesus Christ to bring you to eternal life. Be merciful to those who doubt; snatch others from the fire and save them; to others show mercy, mixed with fear —hating even the clothing stained by corrupted flesh.” (Jude 1:17-23)