Read James 2:14-26
A cold, austere, intellectual faith that does not manifest itself by action is nothing more than a mental assent to the existence of God. James taught that this kind of faith is really no faith at all--it is a dead faith.
It is not enough just to believe that God exists or even to believe that He died on the cross for the sins of the world.
An individual must realize he will be eternally condemned apart from what Jesus Christ did for him personally on the cross, and he must place his faith in Jesus Christ as his personal Saviour.
Such a person who recognizes all that Jesus Christ has delivered him from will have an active, vibrant faith, evidenced by a change of behavior.
James was particularly concerned with the display of works before one's fellowman in order to be justified before others. The works proved that the act of salvation really had taken place. The context of James 2 indicates that James was talking about being justified before men.
James was concerned about looking beyond a person's words to see whether or not his life supported what he said.
In James 2:14 James did not say that the person had faith but that the person only said he had faith. James was really asking, "What use is the kind of faith that only talks and does not act?"
This is the same question raised in verse 16 where the person who claims to have faith does not demonstrate it by doing something for the needy. And James made the point in verse 20 that faith without works is useless, it "is dead."
"Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven" (Matt. 7:21).