Jude was apparently a pretty gullible guy. He also quotes from the
apocryphal book "The Assumption of Moses".
In this book, it describes the events that transpired when Moses died
and was being taken to heaven. The devil attempted to take his body
to burn in hellfire, because Moses killed a person while on earth. Moses
was on the way to hell until Michael interceded (Jude 9).
The reality of the situation is that the book of Jude does not really
belong in the Bible. The book is barely more credible than the non-
cannonical apocryphal books.
As far as which books made it into the Bible and which didn't, it's been
said that the church created the Bible, not the other way around.