Big Idea: It is faith alone that saves, but the faith that saves is never alone.
The word justified that Paul and James use is that kind of word. It has more than one meaning. One meaning of justified is a person being declared righteous by God. That’s how Paul uses it to describe how we are made right with God when we believe (We’ll call that Meaning #1). But the same Greek word also has a second meaning, which is: to demonstrate that something is true, to act in a way that verifies a claim is genuine (Meaning #2). This is how James uses the word.
Doing traditional good deeds, while it is fantastic, is not necessarily going to distinguish you from an unbeliever, because unbelievers can do good deeds. Many of them do. But what will distinguish you, what you won’t see is an unbeliever act in a way that reflects their trust in God. Because they don’t trust Him.