The Book of James was written around 49 AD by James, a leader in the very first Christian church, the Church of Jerusalem.
Members of the Jerusalem church had been removed from the city and spread out to other Roman provinces because of persecution. The letter aims to encourage them during these difficult times. James explains to them that their faith will change not only their conduct but also their character. He gives his readers several tests against which they can measure their faith in Christ. If a Christian fails these tests then their faith is dead.
"Speak not evil one of another, brethren. He that speaketh evil of his brother, and judgeth his brother, speaketh evil of the law, and judgeth the law: but if thou judge the law, thou art not a doer of the law, but a judge. There is one lawgiver, who is able to save and to destroy: who art thou that judgest another?"