Because, having known God, they did not glorify Him as God, or give thanks, but became vain in their reasonings, and their senseless heart was darkened.
having been darkened in understanding, being estranged from the life of God, because of the ignorance which is in them, because of the hardness of their heart;
For if God did not spare the angels when they sinned, but rather confined them to Tartarus, and delivered them into chains of darkness, reserved for judgment;
And the angels who did not keep their own domain, but rather having left their own habitation, He has kept with everlasting chains under darkness for the judgment of the great day;