The cities which gave themselves over to fornication — The word here means, unnatural lusts. Are set forth as an example, suffering the vengeance of eternal fire — That is, the vengeance which they suffered is an example or a type of eternal fire.
Related Commentaries of Jude 1:7
Jude 1:7
7 Even as Sodom and Gomorrha, and the cities about them in like manner, giving themselves over to fornication, and going after strangeb flesh, are set forth for an example, suffering the vengeance of eternal fire.