Because the Christian is free from [the power of] sin does not mean that he is free to sin. Because he is exempt from keeping the law as a means of salvation does not mean that he is exempt from keeping the law altogether. Jesus taught that “No man can serve two masters” (Matt. 6:24) – but neither can he serve none. As Throckmorton has written, “The Christian who is “under grace” and not “under law” must obey. He has changed masters, but he is not his own master; he is not, therefore, free to sin if he wishes.” And if he does? Then although he may believe, he does not have saving faith. For “faith apart from works is dead” (James 2:6). Genuine faith produces a life of disciplined obedience to the moral laws of God – just as a living seed, when properly planted and nurtured, inevitably produces fruit.”
– Joseph Hopkins, The Armstrong Empire, p. 126. The citation is from Burton H. Throckmorton, Jr., Study Guide on Romans, p. 36.