"The Book of Watchers" takes its inspiration from Genesis 6 where it is told that the "sons of God," the angelic "Watchers," come down to earth to procreate with the "daughters of men." The offspring of these unions created the Nephilim, a race of giants.
Because of these fallen angels and their giant offspring the world is corrupted and ruined, filled with evil, prompting the cleansing of Noah's flood. As a part of God's judgment, the angelic Watchers are consigned to prison by the archangels to await the final judgment. And yet, the earth is far from purified. The souls of the giants who perished in the flood remain on earth as unclean spirits who afflict humanity until the judgment. Also, later in 1 Enoch, in "The Book of Parables," future judgment is also to fall upon "the kings and the mighty" who participate in and continue the angelic rebellion of the Watchers by perpetrating ruin and injustice upon earth.
Of course, the story told here by 1 Enoch seems profoundly strange to modern readers of the New Testament. And yet, 1 Enoch illustrates important features of the Jewish apocalyptic tradition, a tradition that many New Testament writers drew upon. Specifically, a working assumption throughout the New Testament is that the world is troubled and enslaved by rebellious cosmic powers. The world is fallen and broken because of demonic influences. Salvation, therefore, is the coming of Christ to defeat these powers, bring them into judgment, and set the righteous free. As 1 John 3.8 says, "the reason the Son of God appeared was to destroy the devil's work." Salvation is the future promise of a full, complete and final eschatological victory over these dark powers. The Day of the Lord, what we call Judgment Day, is the coming of this wrath/liberation, a second Noah's flood, only this time with fire. The righteous, in this view, currently live in a ruined world dominated by demonic powers, powers aided by the "kings and the mighty," and await in hope the return of Christ who will come and rescue them.
Simply put, the righteous stand in Noah's shoes.
Summarized like this, you suddenly see how the New Testament writers shared an apocalyptic worldview with 1 Enoch.
For example, throughout the New Testament the world is described as a place of demonic bondage. Satan is described as the "god" (2 Cor 4.4), "prince" (Eph 2.2), and "ruler" (Jn 12.21) of this world. All creation "groans under bondage" awaiting the "revealing of the sons of God" (Rom 8.19). Salvation is being delivered "from the domain of darkness" and "transferred to the kingdom of his beloved Son" (Col 1.13). The righteous live as "children of light" (1 Thess 5.5) among the "children of the devil" (1 Jn 3.10), awaiting their future emancipation on the day of coming judgment:
For they themselves report concerning us the kind of reception we had among you, and how you turned to God from idols to serve the living and true God, and to wait for his Son from heaven, whom he raised from the dead, Jesus who delivers us from the wrath to come. (1 Thess 1.9-10)
The future reign of God comes to earth after Christ defeats the rebellious angelic powers, along with the "kings and the mighty":
Then comes the end, when he delivers the kingdom to God the Father after destroying every rule and every authority and power. For he must reign until he has put all his enemies under his feet. The last enemy to be destroyed is death. (1 Cor 15.24-26)
Beyond these apocalyptic references to cosmic bondage and awaiting an eschatological emancipation, sprinkled throughout the New Testament are also references to the rebellious angels and the unclean spirits of 1 Enoch. As we know, the Synoptic gospels are full of stories where Jesus is exorcising unclean spirits. As it says in Acts 10.38, Jesus "went about doing good and healing all who were oppressed by the devil." Michael the archangel casts Satan out of heaven in Revelation 12. The New Testament also describes the rebellious angels being bound in prison:
And if God did not spare the angels who sinned, but rather cast them into Tartarus in bonds of nether darkness, held there for judgment, and did not spare the ancient cosmos, but preserved the eighth person, Noah, a herald of justice, having brought a flood upon the cosmos of the impious... (2 Peter 2:4-5)
And the angels who did not maintain their own position of rule, but instead deserted their proper habitation, he has kept in everlasting chains under nether gloom for the judgment of the Great Day. (Jude 1:6)
And lastly, in a sexual echo to the Watchers lusting over "the daughters of men" in Genesis 6, women are asked to dress modestly in church "because of the angels" (1 Cor 11.10).
Much of all this, for regular readers, are things I've written about for years. The upshot, or theological take home point if you are wanting one, is that the connections between the New Testament and 1 Enoch highlight the themes of Christus Victor. Most modern Christians think of salvation as being solely about the forgiveness of sins. But what good is being forgiven if you remain under bondage? Christus Victor highlights our need for rescue and emancipation, our being "trapped" in a wicked, enslaving matrix of idolatry and oppression. And if that seems hard to wrap your head around let me point you Reviving Old Scratch: Demons and the Devil for Doubters and the Disenchanted, my attempt to unpack a Christus Victor theology in an accessible and practical way for modern audiences.
Lastly, I'd also like to point out that scholars of 1 Enoch have pointed out how Jewish apocalypticism functioned as a theodicy and a lament. We, the righteous of God, still find ourselves struggling within a broken, ruined world. We might be forgiven, but we're far from saved. The world is a wreck. We live "between the times." Consequently, in the midst of this ruined world we live as people of hope looking toward a coming emancipation. We are the people who pray Maranatha! Come, Lord Jesus.