Just one question first, where do you get the term "spirit of the law" that's not a biblical term...the "law of the Spirit" is a correct biblical term to describe the obedience to the Spirit and not to the written code of the law.
Also when the term "whole counsel of God" is used by Paul, he refers directly to the "word of grace"
Ac 20:24 But none of these things move me, neither count I my life dear unto myself, so that I might finish my course with joy, and the ministry, which I have received of the Lord Jesus, to testify the gospel of the grace of God.
Ac 20:26 Wherefore I take you to record this day, that I am pure from the blood of all men.
27 For I have not shunned to declare unto you all the counsel of God.
Ac 20:32 And now, brethren, I commend you to God, and to the word of his grace, which is able to build you up, and to give you an inheritance among all them which are sanctified.
So its really hard to reason with you on much of your post because you seem to have established some of your points on error, or lack of understanding?
I'm sorry for using the "spirit of the Law" when you were referring to the "law of the Spirit." The "spirit of the Law" is not my own term. If you Google search, you'll find 80 million + websites that contain it. The Wikipedia page on "Letter and spirit of the law" should provide you a launching pad to further look into the term. It is an idiomatic antithesis meant to demonstrate the difference between obeying the literal interpretation of the words ("the letter") of the law, and the intent of those who wrote it ("the spirit"). It is often employed by people who are trying to make an argument against legalism. For example, someone might say that keeping the seventh day of the week holy by resting from work is keeping the "letter of the law" and may charge that person as a legalist, while on the other hand claiming the Messiah as the fulfillment of the Sabbath and the present need to enter His rest and not keep the seventh day Sabbath, citing Heb. 4 (though I would disagree with this interpretation, but that's for another discussion). The two terms may not exactly coincide but there is certainly at least some overlap, as I imagine you would argue the "law of the Spirit" says the same in contradistinction to the letter, or legal code as you called it. But I'm going to move on because I don't want to get hung up on this since it's not the focus of this discussion.
I appreciate the Scripture you bring from Paul but I believe that he and I are talking about different things. Paul is referring to his task to preach God's revealed will and purpose concerning man's salvation. Yes, this is intimately connected to the good news of the Messiah and the word of grace, but I was talking about that to which a person should look for guidance in their lives, as provided by God: the Scriptures (OT and NT), the example of the Messiah, and the Holy Spirit. The New Testament very clearly demonstrates that Paul and the disciples used all three of these in their teaching. And this method should be of great service to a believer in thoroughly equipping them for every good work, for the three should be in harmony. For example, God states through his Torah-Law not to murder, the Messiah did not murder, and the Holy Spirit is in agreement. The Messiah expounds upon this issue and says to not even hate a neighbor in one's heart. By living this out, the believer demonstrates love for his or her neighbor.
Think I should add some scripture to make the point that at no time does the bible refer to obedience to "the spirit of the law" that implies the literal legalistic standard of the law can be kept by some unclear standard that cannot be shown in scripture.
And at no time does the scriptures tells us we can keep a mixture of the legal standard of the law and the law of the Spirit... you can not be justified by the flesh and the spirit at the same time...works of law and grace...it don't work that way.
Ro 7:6 But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter.
Ro 8:2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.
3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:
4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
2Co 3:6 ¶ Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life. 7 But if the ministration of death, written and engraven in stones, was glorious, so that the children of Israel could not stedfastly behold the face of Moses for the glory of his countenance; which glory was to be done away:
8 How shall not the ministration of the spirit be rather glorious?
2Co 3:15 But even unto this day, when Moses is read, the vail is upon their heart.
16 Nevertheless when it shall turn to the Lord, the vail shall be taken away.
17 Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty. 18 But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord.
There are many lofty theological statements being made in this thread. I appreciate that is your style, but not so many practical statements are being made. I have simple questions for you that need simple answers. I'll take the blame for not being clear in my earlier questioning, which has made it difficult for you to answer. My practical concern is: How should a believer live their life? What should they do and what should they not do? These are the basic questions a new believer will ask, and we should be prepared to answer these types of questions and also direct them to the proper resources to further discern matters. I have already stated that I believe the Scriptures (OT and NT), the example of the Messiah, and the Holy Spirit are these resources. Here are my simple questions for your simple answer:
1. When you are investigating a practical matter of faith concerning how to live your life, which resources do you personally consult? And does this include the OT Scriptures? Do the commands that God spoke through the Torah-Law have any part in your investigation? What I'm really getting at is this: How do you test what the Holy Spirit places on your heart?
2. I'm still fuzzy on your definition of legalism. Can you please define it more clearly, specifically, what does it mean to obey God by the "letter" as opposed to the "spirit"? Can you give a practical example of each of these? Does consulting the commands that God spoke through the Torah-Law as part of one's investigation make them a legalist? For example, when I think the Holy Spirit has placed on my heart that killing a person is not fulfilling the summary command to love one's neighbor as yourself, and I want to investigate and test this, does it make me a legalist to reference the command found in the Torah-Law (specifically found in the ten commandments) as evidence of this truth? (Additionally, I would reference the example of the Messiah).
I have many more questions about your views of legalism, but I'll stop here for now. I also suspect that you and I interpret Paul quite differently but I'll leave that for another post.