Romans 7:7 : What shall we say then? Is the law sin? God forbid. Howbeit, I had not known sin, except through the law: for I had not known coveting, ex-cept the law had said, Thou shalt not covet. Hence, the law Paul had in mind included the command, "Thou shalt not covet," which itself was one of the Ten Commandments. The Ten Commandments were a part of that law from which these brethren had been de-livered.
Because people violated the law, and there-by became sinful, did not prove the law to be sinful. The law defined and condemned sin. Paul had not known coveting--that is, he had not known the real nature of coveting--had not the law said, "Thou shalt not covet." Then he knew coveting--knew the nature of it, knew it to be sin. At the time Paul learned coveting to be sinful he was under the law of Moses, and it was his only source from which to learn the nature of coveting. Any one can now learn from the gospel of Christ the sinfulness of coveting. In fact, the gospel of Christ condemns coveting as idolatry, and thus condemns coveting more severely than does the law.