I think that, lurking under the surface of the massive discussion here, there was a deeper controversy which remained unstated but determined the positions the two sides took.
It became clearer towards the end of that discussion that the different views on how to relate the actions of Christ and the actions of believers were irreconcileable (not just because of a failure on at least one side to acknowledge what the other was saying). Specifically I think there is a fundamental difference of opinion on the question of how God can be pleased with a sinner, or what God will accept from a sinner.
God is pleased with the graces that his Holy Spirit plants in the souls of believers – he is pleased with the righteousness that the Holy Spirit infuses in the soul of each one of his people. He is pleased to accept their works done in faith, their labours of love, their worship of him, their consecration of themselves to him – these are all the outcome of the work of the Holy Spirit in their souls.
But they are all subsequent to, and dependent on, a relationship of reconciliation between God and that sinner who is a believer. The basis of that reconciliation is not, however, the work of the Holy Spirit in them, but the work of Christ for them. This was the point of the original post: that Christ himself alone undertakes on their behalf every thing that is necessary in order for the sinner to be accepted by God.
That includes both making the one-off atonement which reconciles God and sinners in the first place, and also making the ongoing intercession which ensures that that reconciled relationship continues. There is nothing that a sinner can contribute to either of these. Atonement and intercession are made entirely for us and on our behalf by Christ and not on the basis of any thing whatsoever in us or about us. God does not accept a sinner’s works or prayers or self-denials along with Christ’s atonement and intercession. They have entirely different purposes: Christ’s activities are in order to secure the sinner’s pardon and acceptance with God; the sinner’s activities (by the enabling of the Holy Spirit) are their means of honouring a reconciled God.
The scriptures never, ever, mingle the works of the believer with the works of Christ, and neither can we. Rather, according to the scriptures, the immediate and only ground of the sinner’s acceptance with God is the righteousness of Christ imputed to them.
Or hear James Buchanan: “There is, perhaps, no more subtle or plausible error, on the subject of justification, than that which makes it to rest on the indwelling presence, and the gracious work, of the Holy Spirit in the heart. It is a singularly refined form of opposition to the doctrine of justification by the imputed righteousness of Christ, for it merely substitutes the work of one divine person for that of another; and it is plausible, because it seems to do do homage to the doctrine of grace, by ascribing to the presence and operation of the Holy Spirit the production of faith, and all the effects which are ascribed to it, wehther these belong to our justification or to our sanctification. …
“Yet, subtle and plausible as it is, nothing can be more unscriptural in itself, or more pernicious to the souls of men, than the substitution of the gracious work of the Spirit in us, for the vicarious work of Christ for us, as the ground of our pardon and acceptance with God; for if we are justified solely on account of what Christ did and suffered for us while he was yet on the earth, we may rest, with entire confidence, on a work which has been already finished – on a righteousness which has been already wrought out, and already accepted by God on behalf of all who believe on his name – and we may immediately receive, on the sure warrant of his Word, the privilege of justification as a free gift of God’s grace through Christ, and as the present privilege of every believer, so as at once to have joy and peace in believing.
“Whereas, if we are justified on the ground of the Holy Spirit in us, we are called to rest on a work, which, so far from being finished and accepted, is not even begun in the case of any unrenewed sinner; and which, when it is begun in the case of a believer, is incipient only – often interrupted in its progress by declension and backsliding – marred and defiled by remaining sin – obscured and enveloped in doubt by clouds and thick darkness – and never perfected in this life …
“The mediatorial work of Christ is … clearly distinguished from the internal work of the Spirit. By the former, all the blessings of salvation were procured; by the latter, all these blessings are effectually applied. The work of the Spirit is not the cause, but the consequent, of our redemption; and it forms no part of the ground, although it is the evidence, of our justification. That blessing, like every other which is included in salvation, depends entirely on the sacerdotal work of Christ …”