I believe that a key position of the early church's teaching is that an inward change of the heart is not genuine if it does not manifest in outward concrete action. That's how you reconcile, for example, Paul's statements on salvation by grace and not works, with James' demonstration of his faith by his works. The works themselves don't save you, it is the sincere turning of the heart and belief in Jesus Christ. Paul made this point firmly to counter others who were teaching salvation by adherence to Jewish ceremonial law. But if your belief in Christ and turning of your heart does not result in changes in how you live, specifically following the commandments of Jesus, then James would question the sincerity of your conviction.