Remember what the Lord Jesus said and what his apostles said? In fact, what Jude points them to, is the fact that Christ and his apostles had foretold that this very thing would happen. Therefore, the presence of these false ones who have crept in is not to be feared as the destruction of Christ's church, but in fact to be recognized as the fulfillment of the Scriptures given by a Sovereign God who rules and overrules even the assaults of his enemies and who, by the action of his enemies, accomplishes his own eternal glorious, yet mysterious, purposes.1
John McKnight
17 But you must remember, beloved, the predictions of the apostles of our Lord Jesus Christ.