Summary: James 2:14-20 (KJV)
14What use is it, my brethren, if someone says he has faith but he has no works? Can that faith save him? 15If a brother or sister is without clothing and in need of daily food, 16and one of you says to them, "Go in peace, be warmed and be filled," and yet you do not give them what is necessary for their body, what use is that? 17Even so faith, if it has no works, is dead, being by itself.
18But someone may well say, "You have faith and I have works; show me your faith without the works, and I will show you my faith by my works." 19You believe that God is one. You do well; the demons also believe, and shudder. 20But are you willing to recognize, you foolish fellow, that faith without works is useless?
14What use is it, my brethren, if someone says he has faith but he has no works? Can that faith save him?
It is easy to say, "I believe," but only saying it means nothing. We must ask ourselves: "Is my faith real or not?"  Because we are saved only through authentic faith, not through false faith. How can we tell if our faith is true or not? We can tell by our deeds. Our deeds – that is, our acts of love – our deeds of love, our deeds of obedience – are the proofs of our faith. If no deeds are accompanying our faith, then such a faith will not save us (see Mat. 7:21)
James asks a symbolic question, "What use is it, my brethren, if someone says he has faith but he has no works? Can that faith save him?" The question has an implied admonition (caution), which is probably given to us in James 2:1 and 3:1.
"My brethren, do not hold the faith of our Lord Jesus Christ, the Lord of glory, with partiality." (James 2:1)
"My brethren, let not many of you become teachers, knowing that we shall receive a stricter judgment." (James 3:1)
These verses state the theme of this section. Now notice the "if" of James 2:2: "For if there should come into your assembly a man with gold rings, in fine apparel, and there should also come in a poor man in filthy clothes." James supposes an example, no doubt, drawing on his own experience. The careful wording suggests a claim to faith, a comment, and a question. A man says, "I have faith." But James claims that he is without works. The claim and the comment constitute a hypothesis. If this is the situation, says James, nothing can be gained from it. Faith of that kind cannot save him, can it? (The implied answer is 'No.') The claim of faith is unsupported by evidence of its reality, for there is no discernable evidence: he has not works. For James, salvation depends on the Word received and obeyed (1:21).
15If a brother or sister is without clothing and in need of daily food, 16and one of you says to them, "Go in peace, be warmed and be filled," and yet you do not give them what is necessary for their body, what use is that?
This is not an actual event: James still says, 'if,' and he still thinks of a brother or sister. An actual event would require a specific person. James is using his imagination and is making a comparison from what we should call social work. His point is that goodwill or a friendly attitude is not enough. He, therefore, repeats his question, "What is the good?" -- Sociologically, in the realm of human welfare, not that of eternal salvation.
Here James says that false faith is like the love expressed in words but not in action. We can easily say to our poor brother or sister that we love them, but if we do nothing to help them, our love is false, worthless – "17But whoever has the world's goods, and sees his brother in need and closes his heart against him, how does the love of God abide in him? 18Little children, let us not love with word or with tongue, but in deed and truth." (1 John 3:17-18). This kind of love benefits no one. In the same way, unless deeds manifest our faith, it is worthless.
17Even so faith, if it has no works, is dead, being by itself.
This is one of the most important verses in the New Testament because it keeps us from misinterpreting some of Paul's teaching. In Eph. 2:8-9, Paul wrote, "man is saved not by works, but through faith." Many people misunderstand Paul and begin to think that they no longer have to do any good works. They suppose that because man is saved through faith, good works are no longer necessary. They forget that Paul taught in other verses that good works are indeed necessary. Paul wrote in Eph. 2:10 that we were created in Christ Jesus to do good works. He also wrote: "the only thing that counts is faith expressing itself through love" (Gal. 5:6).