When Martin Luther was inventing his new version of Christianity, where he decided that whatever he happened to think was right was definitely right, thereby claiming for himself the infallibility that he denied the Church, he ran into a difficulty in that part of the New Testament clearly contradicted his interpretation of St. Paul. A more humble man might have begun to question whether the interpretation was correct. Martin Luther was not a humble man. He considered himself able to judge the epistle of James: these parts he liked, these other parts he did not like.
He wanted to say that faith justifies apart from works. This is mostly because he did not know the meaning of the word “justify”, which means to change a person into someone who does just works. Our faith is not something we hold onto separately from who we are. Our faith changes us. Faith is not a passive possession; it is an active principle.
If our faith justifies us, that means that our belief in God makes us into a better person, but this is not necessarily true. St. James points to an obvious case: the demons. They believe in God but they are not made into better people. We do not need to go to the supernatural realm to find that this is true. People like those Christians who protest at funerals or a child-abusing priest prove the principle right here on earth. They believe in God, but it does not do them much good.
So faith by itself is not sufficient for justification; something more is needed. St. James calls it “works”, but the principle of these works is love. Jesus tells us to believe, but he also tells us to love. Faith without love is dead. I cannot merely wish good things for the poor. “Bye. Keep warm and well-fed.” I have to love them. “Love one another as I have loved you.” Jesus said that. Faith is not enough.
Faith does not require anything from me. I can believe and then go on living as I always have. Faith is cheap; love is costly. Whoever wishes to follow Jesus must deny themself, take up their cross, and follow him. Does this sound like faith? No. Faith cannot lift a cross. Only love can do that. Faith tells us that we should follow Jesus; love is what does the following. Faith tells us who we should love and who loves us; love is what does the loving.