Commentary and explanation. We have here another key text, if we really want to understand the complete message of the Scripture regarding salvation by faith, and what God wants and expects from us, the believers. There are so many texts, in the New Testament in particular, in which we are taught that salvation is by faith alone without the deeds of the law, that someone could be inclined to think that it is enough to believe, and then there is no obligation to do anything else.
Nothing is more false and pernicious.
Paul teaches that justification is attained by faith alone, without the works of the law, by the redemption of Jesus Christ. According to him, good works can't produce or merit the justice of God. There has always been the danger that someone would abuse this teaching and would conclude, mistakenly, that good deeds are not necessary after justification is attained, as proof and evidence of a true faith. There is nothing more obnoxious and contrary to Paul's mind, who so often and in many ways exhorts us to abound in good works. If good works were not necessary as a proof that faith is genuine, Paul wouldn't have talked so persistently about good deeds in all his letters, as we will see later.