Jude 1:6-7

6And angels who did not keep their own designated place of power, but abandoned their proper dwelling place, [these] He has kept in eternal chains under [the thick gloom of utter] darkness for the judgment of the great day,

7just as Sodom and Gomorrah and the adjacent cities, since they in the same way as these angels indulged in gross immoral freedom and unnatural vice and sensual perversity. They are exhibited [in plain sight] as an example in undergoing the punishment of everlasting fire.