In the next phase of Jude's letter and Peter's chapter, they put together several examples similar to these ungodly men. Jude states "I will therefore put you in remembrance..." It is interesting to note that Peter goes in chronological order, while Jude's order is unclear, though it may have made sense to him. This shows what type of writers the men were and what thought processes they went through. Peter was very methodical, Jude passionate. Though both possessed both traits. Both give three examples, two the same, before comparing them to the certain men. Jude tells his readers he will put them in remembrance. Rather than simply speak his warning, which he could have done very well, he also goes back to examples from the Word of God.
The application: Jude saw the Old Testament as an integral part of his warning (Rom. 15:4; I Cor. 10:11). He realized that his words, no matter how wise or how Godly, meant nothing without scripture to back them up. Now obviously his words would become scripture, but he had no knowledge of that because there was no New Testament. Proof that the Old Testament is just as valuable a teaching tool as the New Testament is that it is quoted from by New Testament writers so often. Its prophecies came and will come true. Jesus himself quotes it and uses it to teach. Paul says it's valuable. And each writer and teacher treats it as if it literally happened, because it did. And if it's in the canon of scripture, is it not there for a reason? 1) The Old Testament is valuable. 2) Our arguments and counsel must be backed up with the Word of God. * If someone gives you counsel and can't back it up in the correct context in scripture, don't listen to them!