1 Enoch 1-5 is an introduction to the Book of the Watchers (1 Enoch 6-36). Nickelsburg  argues the superscription to the book is an allusion to Deuteronomy 33:1 and he translates it to make the allusion more clear.

Deuteronomy 33:1 This is the blessing with which Moses the man of God blessed the people of Israel before his death.

1 Enoch 1:1 The words of the blessing with which Enoch blessed the righteous chosen who will be present on the day of tribulation, to remove all the enemies; and the righteous will be saved.

Chapter 1 describes a “day of tribulation” (יום צרה, εἰς ἡμέραν ἀνάγκης) during which the ungodly will be destroyed and a great cataclysm. The chapter is rich with apocalyptic language here: mountains and high places falling down, earth split asunder, etc. This tribulation is a time when the Enoch-Apocalypse“God of the universe” will come forth from his dwelling and “march upon Sinai and appear in his camp” (1:4). This awesome event will cause all to tremble, even the Watchers, the angelic beings who constantly observe the actions of God.

This arrival of God is for judgment, as 1:9 states: “He will come with ten millions of his holy ones in order to execute judgment upon all.” This verse is used by Jude in the New Testament, but here in 1 Enoch it is the theme for the whole Book of the Watchers. With respect to the plot of the book, the judgment is the coming Flood, but it is clear the writer of 1 Enoch is thinking beyond the Flood to a future judgment of God on the wicked in his own day. Like Noah and his family, the elect of the writer’s day will be preserved from this coming judgment: “to the righteous he will grant peace.” The phrase “the elect” will be repeated throughout the Book of Watchers.

Chapters 2-5 are speculative wisdom not unlike Job 38-41. The writer invites his readers to examine the orderliness of creation and observe that God does not change. The natural order is a progression of seasons which follow very precise patterns and laws. In 5:4 he turns this into a condemnation of the wicked: “But as for you, you have long transgressed and spoken slanderously….” Verse seven then turns to the righteous, who will have “joy and peace in the earth.”

After the judgment, wisdom will be given to the elect who will all live and not return again to sin, being preserved from the plagues and wrath (5:7). This is not necessarily immortality since verse eight says they will live out the complete designated number of their days. Verse 9, however says their lives and happiness will “increase forever.” Isaacs says some manuscripts modify this to “and their lives shall be increased in peace,” taking away some of the ambiguity OTP, 1:15 note v, on verse 10). Nickelsburg agrees with this translation.

Like many of prophetic books, 1 Enoch begins by sounding several key themes. First, judgment is coming on the wicked. Like the Flood, this will judgment will be a cataclysm which destroys all. But second, the elect will be preserved in from this coming tribulation. Like Noah’s family, Enoch’s community may suffer, but they will be ultimately preserved and vindicated when the final judgment arrives. These are themes found in many apocalyptic texts; in the New Testament, Revelation promises judgment is coming and the preservation of the elect through that time of persecution.