But now we have been rendered ineffective from the law, having died in that which we were confined, so that we serve in newness of Spirit and not in oldness of the letter. (Romans 7:6).
“Rendered ineffective” refers to something that no longer functions properly. In Christ, the body of the sin nature has been rendered ineffective in that, while we are walking in the newness of life we have in Him, the sin nature cannot bring its desires to completion. Its cravings simply do not work themselves out anymore, because they do not pertain to our life in Christ.
Having been freed from the law—for all who are in Christ are not under law but under grace—we now have the freedom to live out the righteousness we possess in Christ, apart from the law. This is accomplished by training our senses to discern between what is proper and what is wrong, through putting off the old man and putting on the new, who is created in righteousness and the piety of the truth. Since we are now sons, we have no need for the law, for we are able to mature and walk in a manner worthy of our calling as we govern our lives by the desires of the Holy Spirit and keep Christ’s commandments: to love other Christians and to abide in Him (1 John 3:23–24).