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

1:9 Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, durst not bring against him a railing accusation, but said, The Lord rebuke thee.