For what the Law had no power to do, weak through the flesh, God sending that his son in likeness of sinful flesh and concerning sin condemned sin in the flesh so that the righteous requirement of the Law is fulfilled in us the ones walking not according to the flesh but according to the Spirit (Romans 8:3-4)
I have written about this in the past and I still come across those who do not understand that we live in a new covenant, bound to Christ, not to the old covenants in the old testament. Going back to the old is not a good thing and putting people under the Law will cause sinful nature to increase and become more sinful, this is how the Mosaic Law was weak according to the flesh. Laws nor serving will mature anyone in regards to fulfilling God's righteous requirements. The new covenant introduces a new living way (not the old written code nor a fleshly way) but a spiritual way that fulfills the righteous requirements of the law.
because the mind of the flesh is hostile to God, not submissive, submitting not to the laws of God, in fact it has no power (Romans 8:6-7)
Living according to rules, regulations, decrees, and handwriting, which Paul also calls the "written code" or "letter of the law" is against the new covenant principles. Decrees or elemental principles, like do not touch, handle, or taste have no power to overcome the sinful desires of the flesh (Colossians 2:21). Paul writes to the Galatians of this kind of justification by the law that it is a severing from Christ and a falling from grace (Galatians 5:4). It is to undo what Christ has done and it is not walking in the new living way of the Spirit.
having canceled the certificate of debt, its legal demands against us, which exist hostile to us also taking it away by nailing these to the cross (Colossians 2:14)
There was a dividing wall but Christ has torn it down making to himself one new man from two, breaking down the hostility, in his flesh. Jesus condemned sin in the flesh dying in the flesh as a sacrifice for sin and to bring in a new covenant. And in his death, we are united, crucified with him in the flesh so that we live in a new living way.
do you not know brethren (for I speak to the ones knowing the law) that the Law is ruling a person only so long as he lives?... now at the present released from the Law having died to that which held us captive so that we serve in newness of Spirit and not the old written code (Romans 7:1-6)
We are bound not under the Law. We are a new creation in Christ made alive when we were dead in our trespasses and sin, now made to walk according to the Spirit and not the written code. Paul gives us this analogy using marriage; if the husband dies the wife is free from the Law and she can remarry because she is no longer bound to the marriage covenant. In the same way, we have died with Christ, according to the flesh, therefore a dead person is not bound to the Law. And those dead with Christ will also live with him.
so that the righteous requirement of the Law is fulfilled in us the ones not walking according to the flesh but according to the Spirit (Romans 8:4)
The laws of God are spiritual and man in sinful nature is carnal (Romans 7:14). The carnal man can not submit to the laws of God (Romans 8:6-7). This is how the Law was weak through the flesh. Lay down the Law and sinful nature will live to its nature, it will rebel. Some would say this is a good thing because it will lead them to Christ. John writes it was Jesus's life which is a light to the world and that he came in fullness of grace and truth (John 1:4, John 1:14). The Law was given to Moses but grace and Truth came through Jesus Christ (John 1:17).
People do not need laws with its fear of punishment, they need Jesus. What good is law abiding citizens if they go to hell? Jesus is fullness from the Father, of grace and Truth. Paul writes we will not rule over sin under the law but under grace (Romans 6:14). And if led by the Spirit we are not under Law (Galatians 5:18). And we read "for the Law made nothing perfect (mature) now a better hope was introduced, through which we draw near to God" (He brews 7:19). The Law was weak through the flesh but God's Grace is sufficient for his power is perfected in the weakness of the flesh. The Law could not: grant life or righteousness, take away sin nor deliver the "consciousness" of sin, change human sinful nature, and it could not perfect the believer (Galatians 3:21; Hebrews 10:1-4; Romans 7:18-19; Hebrews 7:18-19).
But God through sending his son brought in a new covenant, which was established in his blood. We don't live to the old but to the new, God is doing something new, do you not perceive it? It was prophesied of, God would put his Spirit within us, give us a new heart, and write his laws on our hearts and put them in our minds (Ezekiel 36:26).
This is how God dealt with the Law being weak through sinful nature, Jesus became sinful nature so we become alive to God, he is the second Adam. A spiritual person is born a new of the Spirit, and since the laws of God are spiritual we now have the power to fulfill the righteous requirements of the law. God sent his son, "so that the righteous requirement of the Law is fulfilled in us, the ones walking not according to the flesh but according to the Spirit" (Romans 8:3-4).