I like your post on the law of God and our subjective experience of it. It is perfect and it is the ‘testimony’ of God. James calls it the ‘perfect law of liberty’ (James 1:25) and Romans 7:12 has a categorical statement about the ‘goodness’ of the law.
NAS Romans 7:12 So then, the Law is holy, and the commandment is holy and righteous and good.
Regarding how the law is the perfect message of how God behaves, the tablets of the law are called the testimony, the ark is the ark of the testimony and the tabernacle is the tabernacle of testimony. The aspect of the law never passes away.
Rcv Exodus 16:33 And Moses said to Aaron, Take a pot, and put an omerful of manna in it, and place it before Jehovah, to be kept throughout your generations. 34 As Jehovah commanded Moses, so Aaron placed it before the testimony to be kept.
25:16 And you shall put into the Ark the Testimony which I shall give you.
25:21 And you shall put the expiation cover on top of the Ark, and into the Ark you shall put the Testimony that I shall give you. 22 And there I will meet with you, and I will speak with you from above the expiation cover, from between the two cherubim which are upon the Ark of the Testimony, of everything which I will give you in commandment to the children of Israel.
31:18 And when He had finished speaking with him upon Mount Sinai, He gave to Moses the two tablets of the testimony, tablets of stone, written with the finger of God.
38:21 This is the sum of the things for the tabernacle, the Tabernacle of the Testimony, as they were counted according to the commandment of Moses for the service of the Levites by the hand of Ithamar the son of Aaron the priest.
Your first sentence reminds me of Romans 2:13-15. It mentions how the Gentiles show the work of the law written in their hearts. For example, it seems that everyone has an idea of fairness. That is one of the key features of the law. Sometimes greed gets the better of this idea or clouds it over, but it is still there. But these verses in Romans embody the paradox of the law. “The doers of the law shall be justified,” but, as you say, we cannot do it by our own power.
DBY Romans 2:13 (for not the hearers of the law are just before God, but the doers of the law shall be justified. 14 For when those of the nations, which have no law, practise by nature the things of the law, these, having no law, are a law to themselves; 15 who shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts accusing or else excusing themselves between themselves; )
It is like God is requiring of man something impossible. The Geneva Bible actually translates the Greek word adunatos as ‘impossible.’
GNV Romans 8:3 For (that that was impossible to ye Lawe, in as much as it was weake, because of ye flesh) God sending his owne Sonne, in ye similitude of sinful flesh, and for sinne, condened sinne in the flesh,
‘Impossible’ is a literal translation. ([UBS] adunatos, impossible (e.g., what the law could not do Ro 8.3); weak; crippled (Ac 14.8) - UBS = United Bible Society Lexicon. “The Geneva Bible is one of the most historically significant translations of the Bible into the English language, preceding the King James translation by 51 years.” Wikipedia)
Actually there is precedent for this. For example, in the gospel passage about the rich young ruler, after the young man turned way Jesus said, "With man this is impossible, but with God all things are possible." (Matthew 19:26). Jesus made a demand on the rule that was impossible with man, but possible with God. I think it is like that with the law.
I think Romans 8:4 answers this. I'll do another post to complete this...