Here’s a very important question, and an excellent answer from John Fonville.
Question: “in the realms of both salvation and sanctification, legalism/neonomianism and antinomianism are errors and distortions of the truth and grace of the Gospel, neither of which glorifies God and may challenge a person’s eternal condition. However, my study of the issue makes it seem that antinomianism is an error in far closer proximity to the true Gospel (a la Romans 6:1-2)…So, (my question now) how do we avoid imprecision in our message to avoid this error, as well?”
Answer: This is a great question and one that deserves a careful and thorough answer. I will come back to this in the future when I have more time. For now, I will make a few comments and post a comment from Ralph Erskine concerning the unfounded charge of Antinomianism.
Antinomianism is as much a perversion of the Gospel as Neonomianism.
First, to be sure, the Gospel-Driven Life is not a doctrine of license. Antinomianism is as much a perversion of the Gospel as Neonomianism. Neither error represents the Gospel.
The short answer to this question is: We must understand the doctrine of union with Christ.
The Gospel will not lead to a life of licentiousness because the believer has come into union with Christ (cf., Rom. 6). There are two means by which the Spirit brings the believer into union with Christ: the Gospel and Faith, which is produced in us by the Gospel.
The Gospel will not lead to a life of licentiousness because the believer has come into union with Christ.
Both the Gospel and faith enable the believer to live unto God in holiness. The purpose of saving faith is to receive the fullness of Christ (not just a half-Christ!) and to walk in Him for sanctification. As Marshall puts it, “When you trust in Christ, you will not move toward godless living, but toward holiness.” Faith is designed by God to give us new affections in our inner most being, which we receive out of the fullness of Christ with whom we are in union. When we come into union with Christ, we not only want to live a holy life but we are also empowered to live a holy life. God designed faith for the purpose of giving both the desire and power to live unto God (i.e., pursue holiness).
Marshall writes, “When you trust in Christ, you believe and begin to comprehend that “through Christ, you are dead to sin, and alive to God,” “that your old man is crucified” (Romans 6:2-4), that “you live by the Spirit” (Galatians 5:25), that you “have forgiveness of sin,” that “God is your God” (Psalm 68:14), that “you have in the Lord righteousness and strength,” which enables you to do all things (Isaiah 45:24; Philippians 4:13), and that “you shall be gloriously happy and that you shall enjoy Christ for all eternity” (Philippians 3:20-21)” (Marshall, p. 57).
Concerning the false charge of antinomianism, consider the words of Ralph Erskine,
“…the doctrine of the Gospel is not a doctrine of licentiousness, or carnal liberty, however it be reproached in the world: and if the preachers thereof, who would bring people from the law of works, and from their self-righteousness, be reproached as if they were enemies to holiness I will venture to say it with confidence, in a place where falsehood should be an abomination, that it is a vile slander; for whatever sinful weakness and imperfection may cleave to the preaching or practice of these, who desire to publish this gospel-doctrine, yet the Lord God of gods is witness; yea, the Lord God of gods knows, and all Israel may know, and all whose eyes God enlightens shall know, that this doctrine of dying to the law, in point of justification, is a doctrine according to godliness, and the very means of holiness itself, and of living unto God: if this be Antinomianism, I am content to be called an Antinomian” (Law-Death, Gospel Life, p. 58).
Already Not Yet 
I’ve just Googled to this post, so my comment may repeat your more recent blogs. I have found Turretin most useful in helping me resolve (at least in my own mind) the antinomian neonomian dilema. He asks “Are good works necessary for salvation?” His answer is to distinguish between the status of the believer and his/her purpose. Through the gospel the believer receives a new status and can truly and joyfully say “I am righteous, I am holy, I am perfect, I am God’s child, I am Christ’s brother” and so on. Knowing this new status by the power of God’s living word the new believer is given a new purpose, to be holy, to be perfect, to be righteous, to be a member of God’s family. So she will ask, how am I to be righteous, holy, perfect, a member of God’s family, Christ’s brother and so on? And in asking this finds that the law instructs her in how to fullfil her purpose whilst convicting her, though not really but provisionally, knowing she is already perfect on account of Christ’s completed work.
To my mind Neonomianism is a greater danger than Antinomianism because it is so much harder to detect.
With that in mind, I am vey wary of those who say (from the Puritans onwards) that after the Law sends us to Christ, Christ then sends us back to the Law.
Christ’s promise, in Jeremiah, is that He will write His law on our hearts AND that it will not then be necessary for one to teach his brother how to behave. We need to trust that the Spirit will increasingly do that for each of us, rather than to counterfeit his ways out of fear.
I couldn’t agree more Richard. Thanks for the comment. Pete