Jude 14-15 Enoch, the seventh from Adam, prophesied about them: “See, the Lord is coming with thousands upon thousands of his holy ones to judge everyone, and to convict all of them of all the ungodly acts they have committed in their ungodliness, and of all the defiant words ungodly sinners have spoken against him.
Enoch was Cain’s first son, and also the name of the world’s first city, which Cain named after his son (Gen. 4:17). The prophecy of Enoch mentioned in Jude is found in First Enoch (the first book in a collection of five known today as Ethiopic Enoch). While the writing of the existing manuscripts dates back to the 3rd century to 1st century B.C., the original content is presumed to extend all the way back to Enoch himself.
The Book of Enoch was widely read in Jewish and Christian circles in New Testament times, and portions of all but Book Two have been found among the other ancient Dead Sea scrolls in the Qumran caves. First Enoch, or “The Book Of The Watchers,” quoted by Jude builds on the account in Genesis 6:1-4 of the “sons of God” uniting with the “daughters of men,” resulting in the offspring of giants. The “sons of God” are identified in Enoch as a band of angels (called “Watchers”) who are captured by angels sent from God and imprisoned until the Final Judgment. Jude’s quote from First Enoch (see above) refers to the Day of the Lord and the outpouring of His wrath upon rebellious mankind prior to that Final Judgment Day.
While the Book of Enoch is not inspired Scripture, God in His sovereign wisdom did inspire Jude to quote from it. God used a book that was popular among Christians in the first century, including the apostles, to convey certain truths about the End Times. That does not validate everything written in the Book of Enoch. On the other hand, the New Testament does refer to a specific group of angels who:
Jude 6 …did not keep their positions of authority but abandoned their proper dwelling—these he has kept in darkness, bound with everlasting chains for judgment on the great Day…
1Pet. 3:19b-20a …imprisoned spirits—to those who were disobedient long ago when God waited patiently in the days of Noah while the ark was being built.
2Pet. 2:4 For if God did not spare angels when they sinned, but cast them into hell (Lit., “Tartarus,” which means “pits”) and committed them to chains of gloomy darkness to be kept until the judgment.
This descriptive language borrowed directly from First Enoch compares Enoch with the crucified and risen Christ. Enoch had been sent to the rebellious, imprisoned angels to pronounce God’s judgment. When they asked Enoch to beg God’s mercy on their behalf, God responded with the same declaration of judgment. In 1 Peter 3:19, Jesus, crucified but made alive by the Spirit, “preached” (Lit., “made a proclamation”) to these imprisoned spirits: He is the true Enoch (by comparison) who walks with God, and has overcome sin, death and all the demonic powers of evil. In the words of the apostle Paul:
Phil. 2:10 …that at the name of Jesus every knee should bow, in heaven and on earth and under the earth…