When we see lightning flash across the sky, we expect the roar of thunder to follow. If there were no lightning, there would be no thunder because one causes the other.
It's like that with faith. Just as thunder always follows lightning, good works always follow true faith.
The relationship between faith and works is explained in the New Testament writings of Paul to the Ephesians, and in a brief letter from James. At first glance, these authors seem to contradict each other. Paul insisted, "Buy grace you have been saved through faith,… not of works" (Ephesians 2:8-9). But James declared, "A man is justified [declared righteous] by works, and not by faith only" (James 2:24).
In context, though, we find that James wasn't denying that we are saved by faith, for he referred to Abraham and said that he "believed God, and it was accounted to him for righteousness" (v. 23). That was years before Abraham gave evidence of his faith by preparing to offer his son as a sacrifice (v. 21). Nor was the apostle Paul denying that value of works, for right after stating that we are saved by faith alone he said that we are saved "for good works" (Ephesians 2:10).
We are saved by faith alone, but faith that saves is never alone.