James has just exposed the powerlessness of the Jewish law or of pagan morality to save anyone. We are saved by faith in Jesus alone. Now he clarifies that saving faith in Jesus can never be alone. It is always expressed by a strong desire to do whatever he says. Somebody who claims to believe in Jesus but merely talks about helping the poor and needy within God’s family cannot truly posses saving faith at all.
From the book "Straight to the heart of Hebrews and James"