For if God spared not the angels that sinned, but cast them down to hell: elsewhere called the deep, Luke 8:31, and the bottomless pit, Revelation 9:1, Revelation 11:7 17:8 20:1,3. This implies a change:
1. Of the state of those sinning angels, that whereas before it was the highest among the creatures, now it is the lowest.
2. Of their place, that whereas they were before the throne of God with the rest of the angels, they are now thrust down into a lower place, agreeable to their sin and misery. What place that is we find not expressed in Scripture, and therefore we are not to be over curious in our inquiries after it; but may rest satisfied, that they are excluded from the place of their primitive happiness, and are in a place where they are afflicted with the pain both of loss and sense. And delivered them into chains of darkness: either to be bound, or held with darkness as with chains; or kept in chains under darkness, as Judges 1:6; where darkness may imply the misery and horror of their condition, and chains, their obduracy in their wickedness, their despair of deliverance, their expectation of future judgment, Hebrews 10:27, together with the providence and power of God, watching over and holding them in that condition, till final vengeance come upon them. It is a metaphor taken from malefactors condemned, who are bound in chains, and kept in the dungeon till execution. To be reserved; so kept that they cannot escape. Unto judgment; viz. that of the last day, the time of their full torment, in which the wrath of God, which they feel in a great measure now, will come upon them to the utmost.