God's commandments reveal what should (and shouldn’t) be done. But a common temptation from sin is going against that! Paul talked about how sin resulted in a bad status after encountering the law. But that doesn't mean that the law causes death -- rather it is sin that does it (7:13). In fact, the law's role is a revealer. Paul found that "the law is spiritual, but [he is] carnal" (7:14). From knowing the law, Paul knows that he has a problem.
In fact, Paul himself also has personal struggles with sin. In particular, Paul mentioned that whatever he did he "[does] not understand", whatever he wants to do, he "[does] not practice", and whatever he hates, he ends up doing (7:15). Paul has this struggle while "agree[ing] with the law that it is good" (7:16).
Today, many of us can have similar struggles with Paul. Sometimes we end up doing actions subconsciously without being aware of them, and some actions aren't really good. We sometimes plan to do good but end up forgetting to do that. And many of us have plenty of "bad habits" that we want to get rid of. Also, all of us have done at least one thing that isn't really a good idea on second thought. But the good news is that Paul knows a someone who can help counter said problems.