Paul possesses another preemptive question based on what he has said earlier. Is the law sinful? This is based on the following verses:
The law was brought in so that the trespass might increase. But where sin increased, grace increased all the more (Romans 5:20)
For when we were in the realm of the flesh, the sinful passions aroused by the law were at work in us, so that we bore fruit for death. (Romans 7:5)
If the answer to this question is yes, what are the repercussions?
It would mean that the Old Testament - the Law - would be of no importance to us. Worse than that, it would mean that it was damaging to us. It would mean that Jesus's own claim that he did not come to abolish the Law or the Prophets, but to fulfil them, (Matthew 5:17) would be untrue. It would create a God of Israel separate from the God of Jesus Christ. The Gospel would replace and not fulfil the Law.
The true answer is found in verse 12, clearly stated:
...the law is holy, and the commandment is holy, righteous and good.
He does however show us between verses 7 and 12 that there is some relationship between sin and the Law. He does this by using an expression similar to the Australian colloquialism "yeah, nah!" or the "yes, no", meaning, it doesn't cancel, but there is something there that needs further discussion. And this is the idea that the Law is not sinful, although it is indeed true that the law and sin are related.
So, what is that relationship?
Well, you come to know sin through the Law. Paul uses the 10th commandment, do not covert, as an example. God truly showed us this relationship using the sin that all of us experience and are slaves to. The idea that we are not to covert. Another word is 'desire'. We have all desired a new job, a better job, a better home, something that we desire in our hearts above what we have today. It really is the 'sin of I want", "I want this", and "I deserve that". It causes the manifestation of other sins in our daily lives, including how we view our circumstances (less or lower than someone else) and cause us to elevate something above God in our life. We see it in the New Testament, but it is explained and demonstrated in the Old Testament and through the story of the Israelites. It is the Law that shows us that it is even a sin. It shows the extent and the seriousness of our sin once we're aware that it is a sin. The Law acts like a mirror, showing us not our face, but our heart, our sinful heart!
Paul is extremely personal in this passage of scripture. He is not talking generally, of Christians or the Roman church, he is speaking as though he has had this realisation during a shocking event in his life. We can look at the book of Acts to see his conversion from Saul to Paul. The point at which the scales from his own eyes fell off and he was no longer blind. Read chapter 7 and focus on the I, me and myself details written. This is intimate and very real for Paul.
He describes his own life in verses 9 and 10. Where before knowing the Law he thought he was alive, but he was really dead. Then, once he knew the Law, he realised that in fact he was dead and that sin was alive - in him! Without the Law we would remain oblivious to our sin - we would stay dead, thinking we were alive. But instead, the Law is there - a mirror - showing us that it is sin that is alive in us and that we desperately need a way to be free from our sin - to be saved from our situation - our eternal damnation - we need a saviour.
The story of Israel paints this picture for us. Loved by God, redemption from Egypt, guided to the Promised Land, constant rebellion and turning away from God. God's wrath being administered for their lack of obedience, for not having any fear of Him, living without consequences, The Exile, and then restoration. The Law exposed their ongoing cycle of failure, and the Prophets tell us of God's great redemptive plan.
So the answer to the question is, no, the Law is not sinful, but it does present the opportunity for us to see our own sin, because in fact, the Law is holy, righteous and good. It reveals the power of sin and our own helplessness. The need for someone to liberate us from our sorry state. All of it points to a saviour - the Messiah - Jesus Christ.