Jesus saves us from our sin (Matthew 1:21) and sin is the transgression of the Law of God (1 John 3:4), so there is a direct connection between our gift of salvation and being a doer of the Law of God and the key is to figure out what that is and is not. We can't earn our salvation even as the result of having perfect 100% obedience to the Law of God because it was never given as a way of earning our salvation in the first place, but Jesus graciously teaching us to experience being doer of the it is intrinsically the way that he is giving us his gift of saving us from not being a doer of it. In Titus 2:11-13, our salvation is described as being trained by grace to do what is godly, righteous, and good, and to renounce doing what is ungodly.
Sin is the transgression of Law of God (
1 John 3:4), so the way to sin is not by slavish obedience to it, but just the opposite.
The context of Habakkuk 2 does not preset the righteous living by faith as an alternative way of living that is not in obedience to the Law of God, but just the opposite. In
Isaiah 51:7, righteous are those on whose heart is the Law of God, and in
1 John 3:4-7, everyone who is a doer of righteous works in obedience to the Law of God is righteous even as they are righteous, so the righteous living by faith is describing the way that the righteous live in obedience to the Law of God.
If the letter referred to correctly following God's instructions and that leads to death, then that would mean that God would be misleading us and shouldn't be trusted, but rather the Bible repeatedly states that obedience to the Law of God leads to life and that the Spirit has the role of leading us to obey, so there must something deficient about following the letter that is missing the goal of the law that causes it to lead to death rather than life. In Romans 8:4-7, Paul contrasted those who walk I the Spirit with those who have minds set on the flesh who are enemies of God who refuse to submit to the Law of God.
The Hebrew word "yada" refers to intimate relationships/knowledge gained through experience, such as with Genesis 4:1 where Adam knew (yada) Eve, she conceived, and gave birth to Cain. God's way is the way to know (yada) Him and Jesus by experiencing embodying His character traits, which is the narrow way to eternal life (John 17:3). For example, in Genesis 18:19, God knew (yada) Abraham that he would teach his children and those of his household to walk in His way by being doers of righteousness and justice that the Lord might bring to him all that He has promised. In Exodus 33:13, Moses wanted God to be gracious to him by teaching him to walk in His way that he and Israel might know (yada) Him, and in Matthew 7:23, Jesus said that he would tell those who are workers of lawlessness to depart from him because he never knew them, so the goal of the law is to graciously teach us how to know (yada) God and Jesus by walking in His way, which is His gift of eternal life.
The problem is that someone can go through the motions of obeying the Law of God (following the letter) while neglecting to be a doer of the character traits of God that it was given in order to teach us how to embody and thus neglect to know God and Jesus, which leads to death rather than life. For example, in Matthew 23:23, Jesus said that tithing was something that they ought to be doing while not neglecting weightier matters of the law of justice, mercy, and faithfulness. In Romans 9:30-10:4, they had a zeal for God, but it was not based on knowing Him, so they failed to attain righteousness because they misunderstood the goal of the law by pursuing it as through righteousness were earned as the result of their works in order to establish their own instead of pursuing it as through righteousness were by faith in Christ, for knowing Christ is the goal of the law for righteousness for everyone who has faith. In Philippians 3:8, Paul had been in the same situation where he had been zealous for obeying the Law of God, but not while being focused on knowing Christ, so he had been missing the whole goal of the law and counted that as rubbish.
The way to bear fruit for God is not by dying to His instructions for how to bear fruit for Him, but by dying to a law that was hindering us from doing that, namely the law of sin.
In Psalm 1:1-2, blessed are those who delight in the Law of the Lord and who meditate on it day and night, so do you think that this verse is expressing a correct view of obeying the Law of God?
In Deuteronomy 6:4-7 the way to obey the greatest commandment in the Bible is essentially by. being obsessed with the Law of God. It is absurd to suggest that by being obsessed with following God's instructions for how to worship him that we are worshiping those instructions instead of God and the way to worship God is certainly not be refusing to follow his instructions for how to worship Him. In Matthew 5:14-16, Jesus did not warn against doing good works in obedience to the Law of God by saying that take gory and emphasis away from him, but rather he encouraged us to do them because they give glory to God.
Christ spent his ministry teaching his followers to obey he Law of God by word and by example and his problem in Galatians was not with them being followers of Christ. Can you quote a single person from this forum as saying that they place the Law of God above God Himself? Or are you just arbitrarily assigning that position to some people in this forum?