The General Epistle of Jude designates its author as “a servant of Jesus Christ and brother of James.” It’s message was for Christians wherever unity was threatened by heretical teaching and where Christian doctrinal and moral standards were questioned.

Jude 1

1:7 Even as Sodom and Gomorrha, and the cities about them in like manner, giving themselves over to fornication, and going after strange flesh, are set forth for an example, suffering the vengeance of eternal fire.