James was written by Jesus’ half-brother James, who was a leader in the church of Jerusalem. It is one of the earliest books in the New Testament, which is why it is written to Jewish Christians. At this early date, virtually all Christians are of Jewish descent.
In this chapter, James says some difficult things like rejoicing when we go through hard times and the need to control our tongues. These are both examples of living what we say we believe.
Neither of these examples comes easily to people. Our reaction to difficult times is more likely to complain, and somehow it’s easier to control our behavior than our words. Living what we believe goes beyond the obvious things into our hearts. Our speech and reactions in situations show who we really are.