The phrase “the works of the law” or “the deeds of the law” occurs three times in the book of Romans and six times (in four verses) in the book of Galatians.  What does this term mean?  Let’s have a careful look.

The term is used in the following verses.

Rom 3:20  Therefore by [the] deeds of [the] law no flesh will be justified in His sight, for by the law is the knowledge of sin.

Rom 3:28  Therefore we conclude that a man is justified by faith apart from [the] deeds of [the] law.

Rom 9:32  Why? Because they did not seek it by faith, but as it were, by [the] works of [the] law. For they stumbled at that stumbling stone.

Gal 2:16  knowing that a man is not justified by [the] works of [the] law but by faith in Jesus Christ, even we have believed in Christ Jesus, that we might be justified by faith in Christ and not by [the] works of [the] law; for by the works of [the] law no flesh shall be justified.

Gal 3:2  This only I want to learn from you: Did you receive the Spirit by [the] works of [the] law, or by the hearing of faith?—

Gal 3:5  Therefore He who supplies the Spirit to you and works miracles among you, does He do it by [the] works of [the] law, or by the hearing of faith?

Gal 3:10  For as many as are of [the] works of [the] law are under the curse; for it is written, “CURSED IS EVERYONE WHO DOES NOT CONTINUE IN ALL THINGS WHICH ARE WRITTEN IN THE BOOK OF THE LAW, TO DO THEM.”

In all the occurrences of the phrase “the works of the law”, it is translated from the Greek ergon nomou.  There are no articles “the” in the Greek.  It should be translated “works of law”. As there are no articles, Paul is not referring to specific laws such as the Ten Commandments, but any law of any religion–the laws of God, the laws of Judaism, the laws of pagan religions. 

The phrase “the work of the law” (work in the singular form) occurs just once, and that is in Rom 2:15. 

Rom 2:14  for when Gentiles, who do not have the law, by nature do the things in the law, these, although not having the law, are a law to themselves,
Rom 2:15  who show the work of the law written in their hearts, their conscience also bearing witness, and between themselves their thoughts accusing or else excusing them)

In this verse “the work of the law” is translated from the Greek to ergon tou nomou.  In this case there are articles “the” in the Greek and it should be translated “the work of the law”.  It is evident that here Paul is referring to God’s law.

Conclusion

“Works of law” are any acts of obedience to any law of any religion.