Jude holds up to us the importance of having and making use of historical points of reference. Again and again the author directs his readers to try to comprehend their current travails and challenges in the light of the struggles of their forebears in their own time. The author cites instances from inside and outside of the canonical books to drive home his points:
17 But you, beloved, must remember the predictions of the apostles of our Lord Jesus Christ; 18for they said to you, In the last time there will be scoffers, indulging their own ungodly lusts.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org