>>681343
I use it all the time. In fact it's particularly dense with doctrine that I like to refer to, actually. Many of these are uniquely good New Testament quotes to get from Jude.
Jude 1, preservation of the saints.
Jude 3, the faith which was once delivered unto the saints
Jude 4-13, strong parallel with 2 Peter 2, see all the points that it has
Jude 4, there are false prophets who are crept in unawares
Jude 7, the sodom and gomorrah were destroyed for fornication and "going after strange flesh," and they "are set forth for an example, suffering the vengeance of eternal fire."
Jude 8, called filthy dreamers; see Deuteronomy 13:1-5; MLK Jr.
Jude 9, the archangel didn't bring railing accusations
Jude 11, way of Cain, error of Balaam, gainsaying of Core (see Numbers 16)
Jude 13, damnation described as "wandering stars, to whom is reserved the blackness of darkness for ever"
Jude 14-16, the prophecy of Enoch divinely revealed
Jude 18, mockers in the last time (see also first half of 2 Timothy 3, 2 Peter 3, 1 Timothy 4:1-3, etc.)
Jude 19, they separate themselves
Jude 22-23, save some with fear, pulling them out of the fire
>Is it because it references non-canon books?
It doesn't, someone took what epistle of Jude said and put it in their book is what actually happened.