As with many other subjects on this forum, we tend to run into problems with the words that are used and what was intended by them v. how they are read by different people. You mention the Kabbalist use of the terms neshamah for soul and ruach for spirit being inverted as to your understanding of the words soul and spirit. I agree that it is confusing for the very same reason and prefer to look at the underlying descriptions to sort it out.
IMHO, the challenge you raise in researching knowledge in the Scriptures v. the Greek philosophers would require a considerable preliminary effort to define terms. The Scriptures differentiate between knowledge, wisdom and understanding and wed have to consider that which is a gift of God v. the resulting effort of man (Proverbs 1 and 2:)
Trust in the LORD with all thine heart; and lean not unto thine own understanding. In all thy ways acknowledge him, and he shall direct thy paths. Be not wise in thine own eyes: fear the LORD, and depart from evil. Proverbs 3:5-7
For instance, although Im very much aware of being a new creature in Christ I do see the old me, the carnal me, like some impish, powerless nuisance hanging around in my psyche. She throws me some nasty thoughts now and again and I find myself rebuking her. All of this goes on strictly within my being, and rarely spills over to my contacts with others. I know that Paul struggled with the same issue:
That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit. For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit.
For to be carnally minded [is] death; but to be spiritually minded [is] life and peace. Because the carnal mind [is] enmity against God: for it is not subject to the law of God, neither indeed can be. So then they that are in the flesh cannot please God.
But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his. Romans 8:1-9
So am I a dualist or what?
I confess I find the Scriptures adoption of the language of gnosticism annoying. ;-` But I'm glad that through it captives to that motif have been lead to their freedom.
The flesh vs. the spirit to the Greeks and mystics is a divide of the dimensions of man. But in the Lord's Word to us, it is just what you have said, a distinction between the fallen nature (in all its aspects eternally separated from God) and the new nature (in all its aspects eternally united with Him) and that because it is of the dimensions of God and man fully related!
I don't know the Greek word for "Spirit," used in the declaration, "the mind controlled by the Spirit is life and peace," but the Spirit is the Spirit of God Himself breathed into us by the precious gift of the lain flesh of Jesus the Unifier. And because of this new breath breathed by the willing, all that is of a person has come under it's power, by the authority of the Word it carries.
As I walked out of that cultic church a few years ago, one who was sort of "strongly suggested out" just before I left pointed me in the direction of a book by another man of might, Jesse Penn (mightier than the Body) Lewis. It was so wonderful to be reassured in his book, that God has given me a will -- and a will to be a will! -- a will which is all mine and not ever to be violated, nor dominated, nor dissipated, not by any creature and not even by God Himself. Why? For the very reason He made life: because He did not want to be succumbed to, but to be fully agreed with and very, very, very wilfully embraced. Ho, the difference!
That is a good test of whether one is free from gnostic notions: whether one is confident in God's gift of full person and an autonomous identity in all aspects of our lives, an identity in which we may run to willingly unite with His, yet as two individuals, and yet still in a unity which is utterly autonomous as a new joined relational identity, after the God-Man Himself. We never cease to be any less self in this relationship. However, we find self's other! We find a new fathomless giving of each other, God to me and me to God, a giving past death, that is a new living phenomena in all of creation, not possible had it not been for both the fall of the first Adam and the rise of the Second!
Thus, my reason is free, my emotions are free, my head and heart are free, and my will is enabled to agree with God in winning the soul's ground for the dwelling of one God and me.
Die, to live, yes, in Christ. But done once and for all. And yes, we still have the fallen nature to drag along with us until our earth bound bodies are worn down, but yes, it is not us anymore. It is as you say, just what was. And yes, we still have our old Adamically cursed bodies, but even they as degenerate as they are, are sanctified by what the vessel contains and until the new thoroughly pure flesh is put on.
Oh what we know! Oh WHO we KNOW! (when we are what we may be).
Yes, creation is expanding.
Doesn't look like it to me, A-G! :^) What a beautiful post, through and through. But this is particularly noteworthy, IMO: "I agree with you that the bride of Christ is the collective body of believers (Revelation.) There is however also a personal belonging, or engagement, that we experience until the groom arrives." Thank you so much, A-G!