Watchers Bound Until Judgment Day

Notice the tense. Jude does not say the angels were judged. He says they are being kept - held in chains, under darkness, until a judgment that has not happened yet.
That distinction matters. The binding is custody, not sentence. Something has already been decided about their freedom, and something else is still to be decided about their fate, and the second thing is fixed to a day Jude calls the great one.
And the details are not from Genesis. Genesis records the transgression and says nothing about what followed for the sons of God. The chains and the darkness come from 1 Enoch 10 and 21.
Scripture links:
- Jude 6 - "he has kept in eternal chains under gloomy darkness until the judgment of the great day."
- 2 Peter 2:4 - "committed them to chains of gloomy darkness to be kept until the judgment."
They are in custody, awaiting a court date. Jude wants his readers to know the court will sit.