If you've ever wondered whether the authors of the New Testament were aware of the Book of Enoch, the Letter of Jude removes all doubt. In verses 14-15, Jude directly quotes 1 Enoch 1:9: "Enoch, the seventh from Adam, prophesied, saying, 'Behold, the Lord comes with ten thousands of his holy ones, to execute judgment on all.'"
This is a direct quotation. Jude is treating the Book of Enoch as authoritative prophetic text — not just background reading, but scripture worth quoting in an inspired letter to the churches.
The context of Jude's letter makes this even more interesting. Jude is warning against ungodly teachers who are distorting grace into licentiousness. As his example of divine judgment against the ungodly, he reaches for Enoch — specifically, Enoch's account of the Watchers and their condemnation. The ungodly teachers of Jude's day are repeating the pattern of the Watchers: corrupting what is holy for their own gratification, and facing the same judgment.
Jude also references the story of Michael disputing with Satan over Moses' body — a story that doesn't appear in the Old Testament but does appear in later traditions associated with Enochic literature. Jude's letter is saturated with Enochic background.
This creates an interesting question for canon theology: if Jude quoted Enoch as prophecy, and Jude is in the New Testament, what does that say about Enoch's authority? The early church asked exactly this question. Tertullian thought it meant Enoch should be in the canon. Others disagreed. But no one denied that Jude was quoting it.