3 Beloved, while I was making every effort to write you about our common salvation, I felt the necessity to write to you appealing that you contend earnestly for the faith which was once for all handed down to the saints. 4 For certain persons have crept in unnoticed, those who were long beforehand marked out for this condemnation, ungodly persons who turn the grace of our God into licentiousness and deny our only Master and Lord, Jesus Christ. Jude 1:3-4 (NASB)
Carefully read the passage above my brethren. The writer of the Epistle of Jude is the brother of James, the well-known leader of the Jerusalem church (Acts 12:17; 15:13; 21;18; Galatians 2:9) and, therefore, the half-brother of our Lord Jesus Christ….
In v3 we read that Jude had intended to write a letter on salvation as the common blessing enjoyed by all true believers. This intent was probably to emphasize unity and fellowship among believers as he reminded them that God is no respecter of persons, however, his plans were changed. He doesn’t say why he “found it necessary” to write something else, but what we have in this letter is actually a call to battle for the truth in light of the appearance and infiltration into the Church of apostate teachers.