There have always been competing Christian groups that emphasized works vs faith. As it turns out this debate may be as old as the Bible itself.
Not only does Paul and James appear to be on two very different sides of this debate, but the four Gospels seem to take very different stances.
It’s possible that this is not a contradiction, that “both are true” and there does exist various theological explanations that zip them up together. However, it’s certainly fascinating that both groups of texts focused *solely* on one side of the equation, and fully ignored the other.
See this for more info.