Skimming through a book I picked up last year, Reading Paul’s Letter to the Romans, I particularly enjoyed the essay by Francis Watson on the law. Here is Watson’s very first paragraph which is also a nice summary of the topic.
“Paul uses the word nomos (‘law’) on seventy-two occasions in Romans, and in all but a few cases the reference is to the Torah, the law of Moses whose five books are foundational to Jewish Scripture. Thus the law was given though Moses (Rom 5:14), and before his time 'there was no law' (5:13). The law was entrusted specifically to the Jewish people (2:17), or 'Israel' (9:31), for whom it is a legitimate source of pride (2:24). Gentiles are basically ignorant of the law although they sometimes unknowingly observe it (2:14). The law is associated with wrath (4:13) and with sin or transgression (3:20; 4:15; 5:13; 7:7, 8). It is disassociated from the righteousness of God (3:21), promise (4:13–14), and grace (6:14, 15). Although its commandments are many, they can be summed up in a single negative or positive statement: 'You shall not desire' (7:7), or 'You shall love your neighbor as yourself (13:8–10).”
Francis Watson, “The Law in Romans,” in Reading Paul’s Letter to the Romans, ed. Jerry L. Sumney, Resources for Biblical Studies 73, ed. Tom Thatcher (Atlanta: Society of Biblical Literature, 2012), 93.