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

1:3 Beloved, when I gave all diligence to write unto you of the common salvation, it was needful for me to write unto you, and exhort you that ye should earnestly contend for the faith which was once delivered unto the saints.