Paul is talking about the carnal man, sold under sin. Don't just DO the Christian deed, but in deed, BE the Christian in heart. DO it and BE it, BE it and DO it. True religion has an outward action to God and others and an inward action on the heart. DO and BE a Christian.
True religion makes a difference in the sincerity of concern for the needy.
James does acknowledge that true Christian faith does have its outward expression - godly concern and action in relationship to others. He wants us to be sensitive and reactive to others' emotional and economical distress. Widows and orphans were the most common in distress in biblical days. Today, James might have used the homeless and third world countrymen in his examples. All of these provide an immediate opportunity to express our Christian love.