James 1:1 
James, the slave of God and of the Lord Jesus Christ, sends greetings to the twelve tribes who are scattered throughout the world.

At the very beginning of his letter James describes himself by the title wherein lies his only honour and his only glory, the slave of God and of the Lord Jesus Christ. Withe exception of Jude he is the only New Testament writer to describe himself by that term (doulos) without any qualification. Paul describes himself as the slave of Jesus Christ and his apostle (Romans1:1; Philippians1:1) but James will go no further than to call himself the slave of God and of the Lord Jesus Christ. There are at least four implications in this title.
     (i) It implies absolute obedience. The slave knows no law but his master's word; he has no rights of his own; he is the absolute possession of his master; and he is bound to give his master unquestioning obedience.
     (ii) It implies absolute humility. It is the word of a man who thinks not of his privileges but of his duties, not of his rights but of his obligations. It is the word of a man who has lost his self in the service of God.
      (iii) It implies absolute loyalty. It is the word of a man who has no interests of his own, because what he does, he does for God. His own profit and his own preference do not enter into his calculations; his loyalty is to him.
     (iv) Yet, at the back of it, this word implies a certain pride. So far from being a title of dishonour it was the title by which the greatest ones of the Old Testament were known. Moses was the doulos of God (1Kings8:53; Daniel9:11; Malachai4:4); so were Joshua and Caleb (Joshua24:29; Numbers14:24); so were the great patriarchs, Abraham, Isaac, and Jacob (Dueteronomy9:27); so was Job (Job1:8); so was Isaiah (Isaiah20:3); and doulos is distinctively the title by which the prophets were known (Amos3:7; Zechariah1:6; Jeremiah7:25). By taking the title doulos James sets himself in the great succession of those who found their freedom and their peace and their glory in perfect submission to the will of God. The only greatness to which the Christian can ever aspire is that of being the slave of God.

William Barclay (commentary on James 1:1)