"Did that which is good, then, bring death to me? By no means! It was sin, producing death in me through what is good, in order that sin might be shown to be sin, and through the commandment might become sin beyond measure."
Paul anticipates an objection from his readers regarding what he'd been teaching. Someone might ask, "Are you teaching that the law itself, which is good, bring you spiritual, eternal death?" Paul shouts back, "Of course not! By no means!" The law, within itself, is holy, righteous and good (see verse 12). The law didn't produce death in our hearts. It only proves death in our hearts. It reveals all the evil that lurks within. It shows sin to be sin. Through all the commandments, we see the boundless measure of sin within. We do disobey not only the 10th Commandment (the one that pricked Paul's heart), but ALL of them. Our hearts are wicked, evil and selfish beyond words. We are condemned by the law.
In this helpless, hopeless condition, how can we be saved? That's the question Paul is raising for all his readers. It's the most important question any of us can ask? By our works unto the law? But none of us can ever do enough before God to please him. Therefore, we are desperately lost. The only other option is grace, the grace of Jesus given to us to forgive us of our sins, not based on works but a gift.
What other option can there be? How else can we be saved except for God's grace through Jesus Christ?
That's the argument Paul is making in these verses.
It's a very powerful argument. And it's eternally important that we too enter this debate.