THE Epistle of James is ... not in the true sense of the word a letter, but rather an address in the form of a circular letter to all Jewish Christians within the pale of Christianity, which was already quite widely disseminated.
What, however, the author recognizes as fundamental in the spiritual condition of his readers is the worldliness and superficiality of their Christianity. With the multifarious sufferings . . . they began to lose patience and their hearts were divided between God and the world. Alongside of flattery to the rich, there is contempt for the poor. . . . Alongside of the prayer for means to satisfy their pleasures, there is impious security on the part of the well-to-do. Stress is laid upon the profession of faith, which was a subject of wrangling and dispute, and everyone was eager to impart instruction; but there were few signs of application of faith to practical life. . . . After an exhortation to be steadfast and prudent in trials, there follows the lesson that the temptation to fail in the hour of trial proceeds from . . . sinful inclinations, not from God, the giver of all good, . . . and to this is attached the admonition to assimilate this word of truth in a humble and obedient spirit. Later on there are special warnings against the errors and faults named above. The conclusion consists of various brief admonitions. The simple style of the letter suits its practical contents admirably, following the method of the didactic writings of the Old Testament, in which the single proverbs are strung together in groups like rows of pearls. Instead of the precision of Paul's keen, logical thinking, there is found more rhetorical amplification. . . . Nevertheless, the moral teachings of Jesus, principally those of the Sermon on the Mount, are much more freely used than in any other writing of the New Testament.
—From the New Schaff-Herzog Encyclopedia of Religious Knowledge