The great difficulty in this discussion is trying to precisely put one's finger on the problem in a way that those who are being criticized will recognize themselves in when criticized.
It's not really the issue that this movement denies the necessity of personal holiness. You will hear them speak of the third use of the law as well as the definitive nature of sanctification.
Where I believe the main point of departure is on the definition of the Gospel and the relationship of the Law to it. I was listening to D.A. Carson recently who observed that the problem with some teachers is not that they don't have certain insights into an aspect of theology but that they make certain issues all-controlling.
I believe the all-controlling issue in this is a Law/Gospel distinction that sees Law as "Do" and Gospel as "Done". Put another way, Law is imperative (do this) while Gospel is indicative (Christ has done). You will often here this movement speaking of a confusion of the Law/Gospel distinction whenever law is seen as anything sanctifying in the life of the believer. Here's an excerpt that describes the view well:
...Paul even moves back and forth between those two senses, even in the same breath (Rom 3:19-22; Gal 3 and 4, etc.). The WCF refers to “the time of the law” and “the time of the gospel,” which fits that historia salutis sense. In that sense, of course, law and gospel have continuity, not antithesis. It’s from earlier to later, infancy to adulthood, more obscure to clearer, etc.. Also, the law still functions in the covenant of grace. Even though our personal performance of the law’s conditions isn’t the basis (unlike the national covenant with Moses as its mediator), the covenant of grace includes the commands of the moral law. Our relation to the law has changed in Christ. It can’t condemn me, which is why Calvin called the third use its “principal use.” However, the law’s job description has not changed. It can only do what “law” can do: reveal what God approves and disproves; judge and guide. So now it guides me. It tells me what’s pleasing. However, the law itself does not tell me what God has done in Christ for me. The gospel isn’t restricted to justification. In Romans 6, for example, Paul answers the antinomian charge by showing how the gospel is wider than forgiveness—it includes regeneration and sanctification. But our faith and obedience are always a response to the gospel, not the gospel itself. I am aware of some of those places where some Puritans said that Christ has turned the bitter commands into precious promises, but in my view that’s not a helpful way of putting it—although I agree wholeheartedly with their point. I think they’re saying that Christ has taken the fire out of Sinai, so that we hear his commands as a Father’s will rather than a Judge’s sentence. I’m all with them there. However, I think it’s a dangerous category mistake to say anything close to the idea that in Christ the law becomes gospel and the gospel becomes law.
I think, on the surface of things, nothing seems out of the ordinary. Sanctification is preserved in the Gospel after all. The issue, if you can detect it, is how the Gospel is defined.
Notice that law is seen as commands and Gospel is seen as Promise and so there's no way in which commands can become promise. A divide is made because the controlling Law/Gospel distinction is of this nature.
What the WCF operates on, however, isn't a view of the Gospel or the Law that sees one as Promise and the other as command. The classic understanding is that, while we are dead, Law only condemns because our flesh will only rebel against its holy precepts. In the Gospel, however, men are brought from death to life. The reason the Puritans spoke of turning commmands into promises is not because the nature of the law has changed (it reflects God's holy character) but because the nature of the
person has changed.
This is why Calvin spoke of the
primary use of the law as what we might call the 3rd use. If I'm born again, the law does not come to me as "Do this and you will live..." but "Because you're alive, you have been set free to do this...." As Luther put it: We are free to obey. Slavery in the Scriptures is not that we are enslaved to commandments but that we are slaves to sin. The freedom we have in Christ is the freedom to obey His commands. Our new natures are not in hostility to God so that all we can do is sin.
This is why the Law=Do and Gospel=Done distinction is not helpful but, because it's all controlling, the only way the Law can be viewed is as something that reveals a command that I cannot perform. Notice how it is noted that it "...cannot become the Gospel..." because the Gospel is restricted to the notion that God has Promised to accomplish everything. When I'm talking about God accomplishing righteousness for us then I'm talking Gospel in this schema but when I'm talking about commands of God that we can't accomplish perfectly I'm talking Law.
But this gets back to my note about how Carson said that people tend to make one true aspect all controlling. It's not that the Gospel is not a Promise or that I have to then call commands I cannot perform perfectly Gospel. The issue is this: the Gospel is defined much more broadly than just God accomplishing righteousness in Scripture. The Gospel is also God transporting us from death to life. The Gospel includes our participation in the age to come where all things are new. It includes that we were slaves ton sin and now are free.
I am not the Gospel and my actions are not the Gospel but it is the Gospel that made it possible for me to live a new life. I'm adopted by God and He's now my father. That's Gospel. It's not merely a promise of something that God has accomplished but it is a present reality for me because I'm now His son. I'm freed to obey God
now. It's not only a promise of that which God has accomplished but a reality that I enjoy today. How am I to view the commands of my father? Must I choose to think of them as unable to do anything but condemn me for my inability to perform them? May I not delight in them? May I not see in these the words of my Father? When He is disciplining me by my failure to be a son, may I not stay rooted in the Promise of my status as a son, and view the discipline of the law not as condemning but as a rod in the hand of a loving Father?
You see, I think the problem is that the Law/Gospel distinction makes us suspicious of God's law as only being able to condemn me and not as anything that can sanctify. Notice how the above sees only the Promise of accomplished work (done, indicative) as the only thing that can sanctify. The Law cannot serve that purpose under that schema. Put plainly, they believe the Law cannot sanctify because they view Promise/Done/Indicative as Gospel and, by this definition, only this can sanctify. The nature of the Gospel is limited in the process to describe the things that God has done. Now, in saying this, I'm not saying it's not utterly fantastic to note what God has done but I also think it sad to limit the definition of the Gospel to make God's law impotent to sanctify when I believe that part of what the Gospel bears with it is a change in our status to where the Law can now serve the purpose it was truly intended for.
I know this has been circuitous but I hope helpful. It's not so much that this idea denies law altogether and it doesn't deny definitive sanctification altogether. What is believes, however, is that only the announcement of God's completed work can be the means for sanctification. It tends to downplay or outright deny any role that the law can have in sanctifying the believer. Any effort or sweat that the believer is seen to put into this is viewed with suspicion as the believer is not resting in Christ's accomplished work.
From my perspective, this is a basic denial of the light of nature and our own analogy of human parenting. My sons never, for one moment, doubt that they are my sons. I've seen them work really hard to please me and never, for one moment, did they believe they were doing this in order to be sons of Rich. They did this because they were my sons. We need to return to a view of sanctification that has a proper view of the Gospel and the Law.
Before Christ came we were dead in sins and trespasses. In our blindness we thought this was the way: "Do and live".
When the love of Christ dawned in our hearts, our lives were transformed. We were no longer slaves to sin but slaves to Christ. Christ put sin as power to death on the Cross for us. We have been united to His indestructible life in the Resurrection and we are freed to obey. We live and because we live, it opens up the entire Kingdom of God to us where the commands of God are not a burden but the loving words of a Father.
This is the proper distinction. It is the distinction between death and life. It is not a distinction between Gospel=Done and Law=Do. The Gospel includes that Christ has secured our
freedom to obey and the new universe created by the Gospel makes the
entire Word of God sanctifying to that end.
NOTE: I've read and re-read what I wrote and am convinced it's a bit rough and needs some editing. I'm sorry if I'm not as articulate as I could be if I had more time but I typed this out quickly so please forgive me if there's stuff that's difficult to read.