“While we were living in the flesh, our sinful passions, aroused by the law, were at work in our members to bear fruit for death. But now we are discharged from the law, dead to that which held us captive, so that we serve not under the old written code but in the new life of the Spirit.”Romans 7:5-6
From this passage it’s evident that when Paul says our passions were aroused by the law, but that now we are discharged from the law, he means the Law of Moses. What else could “the old written code” in verse 6 refer to? It can’t refer to law in general, that is, the moral law, because of the word “old.” Not because the moral law isn’t old, but because “old” in this context implies “superseded.” And further, because of the word “written.” We don’t refer to the moral law as a written law. Not that parts of it aren’t written down, they often are. But in specifying that the law he’s referring to is a written law, Paul indicates that it’s primarily a written law; which the moral law is not.