I realize the dust has settled on the recent so-called "sanctification debate," and it is not my intention to cause further ripples in already placid waters. What I'd like to do is just post a couple of quotes that I hope would tend to the appreciation that Dr. Mark Jones' position on sanctification, as it relates to final salvation, is actually of rich, Reformed pedigree (if this has not been proven already!).
Alongside Reformed luminaries such as John Calvin, John Owen, Francis Turretin, Gisbertus Voetius, Petrus van Mastricht, and Herman Witsius, Dr. Richard Gaffin of Westminster Theological Seminary gives MJ a high five. Compare MJ's introduction to Dr. Gaffin's work with a portion of the said work that is relevant to the discussion:
"A second area of interest in present-day polemics regarding justification concerns the role of works at the final judgment. Balancing the doctrine of justification by faith alone with the teaching of Scripture that Christians will be judged 'according to their works' remains a difficult task. Some imagine that the classical Reformed position on Romans 2:5–16 has in view only a hypothetical possibility, which in actual fact cannot be true of any sinner, whether redeemed or not. But many Reformed theologians did not adopt the hypothetical view of this disputed passage (though vv. 5–11 and 12–16 were sometimes distinguished), such as Martin Bucer, John Ball, Thomas Manton, Herman Witsius, Wilhelmus à Brakel, and Petrus van Mastricht. For example, Mastricht put forth the view that there are three stages of justification that should be 'diligently observed.' These are not different justifications, but distinct stages in the one justification by faith alone. In the first stage, 'establishment,' in which man is first justified, the efficacy and presence of works are entirely excluded for acquiring justification. In the second stage, 'continuation,' works have no efficacy, but works must be present, as we see in James 2:14–16. In the third stage, 'consummation,' in which believers gain possession of eternal life, good works have a certain 'efficacy,' insofar as God will not grant possession of eternal life unless they are present. Interestingly, Mastricht adduces Romans 2:7, 10 in support of his view. Like Mastricht, Professor Gaffin also rejects the view that Romans 2:5–16 is hypothetical. For that reason, both authors hold firmly to the Reformed view that good works are a necessary condition (consequent, not antecedent, to faith) for salvation. Spirit-wrought good works are not only the way of life, but also the way to life/salvation (see WLC 32). Yet the position expounded in this book is perhaps more persuasive than what one finds in Mastricht’s significant work." (Mark Jones, Intro to Dr. Richard Gaffin's By Faith, Not By Sight)
"For Christians, future judgment according to works does not operate according to a different principle than their already having been justified by faith. The difference is that the final judgment will be the open manifestation of that present justification, their being 'openly acquitted,' as we have seen. And in that future judgment, their good works will not be the ground or basis of their acquittal. Nor are they (co-)instrumental, a coordinate instrument for appropriating divine approbation as they supplement faith. Rather, they are the essential and manifest criterion of that faith, the integral 'fruits and evidences of a true and lively faith,' appropriating the language of the Westminster Confession of Faith, 16.2. It is not for nothing, and not to be dismissed as drawing too fine a distinction exegetically to observe, that in Romans 2:6 Paul writes 'according to (kata) works,' not 'on account of (dia) works' (which would express the ground) nor 'by (ek) works' (which would express the instrument)...Their future justification, as we have been speaking of it, will have already taken place in their resurrection, with the de facto declarative, forensic, justifying significance it has in Paul, as we have pointed out above. That means, further, that for believers the final judgment, as it is to be according to works, will have for them a reality that will, as we have already noted, reflect and further attest their justification, which has been openly manifested in their bodily resurrection.
It would be perverse, then, to read Paul’s teaching on the final judgment, as well as my discussion of it here, as leaving believers in this life, in the face of death, uncertain of the future—unable to know for sure the outcome for them at the final judgment and wondering whether they have produced enough 'good works' in this life for a favorable verdict at that point entitling them to eternal life. To the contrary, everything at stake here, including their assurance, depends on Christ—specifically, if it needs to be said again, his finished righteousness, imputed to them and received by faith alone. At the same time, Paul’s teaching on the final judgment and the role it will have for believers does put in ultimate perspective the integral, unbreakable bond he sees between justification and sanctification, and the truth that faith as 'the alone instrument of justification is not alone in the person justified' (Westminster Confession of Faith 11.2)." (Richard Gaffin, By Faith, Not By Sight)
Perhaps not really all that surprising, Walter Marshall (a Puritan), in his work that is considered as the definitive resource on the Reformed doctrine of sanctification, is another one with his palm wide open for MJ. Notice the "title" language by Marshall as something that is equivalent to Mastricht's "right" and "possession" distinction mentioned by MJ in that infamous Meet the Puritans blog post:
"Protestants generally acknowledge, that good works are the way in which we are to walk to the enjoyment and possession of the glory of Christ, though a title to Christ and His glorious salvation be freely given us without any procuring condition of works...We then conclude that holiness in this life is absolutely necessary to salvation, not only as a means to the end, but by a nobler kind of necessity, as part of the end itself. Though we are not saved by good works, as procuring causes, yet we are saved to good works, as fruits and effects of saving grace, which God has prepared that we should walk in them (Eph. 2:10). It is, indeed, one part of our salvation to be delivered from the bondage of the covenant of works; but the end of this is, not that we may have liberty to sin (which is the worst of slavery) but that we may fulfil the royal law of liberty, and that we may serve in newness of spirit and not in the oldness of the letter (Gal. 5:13; Rom. 7: 6). Yea, holiness in this life is such a part of our salvation as is a necessary means to make us suitable to be partakers of the inheritance of the saints in heavenly light and glory; without holiness we can never see God (Heb. 12:14), and are as unfit for the glorious presence as swine for the presence chamber of an earthly prince." (The Gospel Mystery of Sanctification)
With that I leave you with a recommendation: Read MJ's "Antinomianism" along with Dr. Gaffin's "By Faith, Not By Sight." These two books have a perichoretic interpenetration that is bound to leave you with an understanding of salvation that is both deep and doxological—in an unadulterated Reformed way.