If you are right, Jesus died for nothing.
Nothing that I said means that Jesus died for nothing. In Titus 2:14, Jesus gave himself to redeem us from all lawlessness and to purify for himself a people of his own possession who are zealous for doing good works, so becoming zealous for doing good works in obedience to the Mosaic Law is the way to believe in what he accomplished through the cross (Acts 21:20), while if you are right, then while if you were right, then that would undermine everything that he accomplished.
The Law came through Moses, grace and Truth through Jesus.
In Psalms 119:29-30, David wanted to put false ways far from him, for God to be gracious to him by teaching him to obey the Mosaic Law, and he chose the way of faithfulness, so this has always been the one and only way of salvation by grace through faith. Likewise, in Psalms 119:142, the Mosaic Law is truth, so grace and truth came through the Mosaic Law, and Jesus is God's word made flesh, so grace and truth also came through him because he embodied that grace and truth by setting a sinless example of how to walk in obedience to the Mosaic Law.
The Law was the covenant God made with Israel, no one else. It's not that people can't keep God's Law. It is that they will not. The heart of man is deceitful above all things and desperately wicked. All the Law does is to expose the desperate condition of man's heart.
In Matthew 4:15-23, Jesus began his ministry with the Gospel message to repent for the Kingdom of God is at hand, which was a light to the Gentiles, and the Mosaic Law was how his audience knew what sin is (Romans 3:20), so repenting from our disobedience to it is a central part of the Gospel message, which he commissioned his disciples to bring to all nations (Matthew 28:16-20). So Jesus spent his ministry teaching his followers to obey the Mosaic Law by word and by example, and someone can choose whether or not to follow him, but they can't follow him by refusing to follow what he taught. In Deuteronomy 30:11-20, Moses presented a choice between life and a blessing through obedience or death and a curse through disobedience, we have an identical choice in regard to whether or not we are going heed the Gospel message, and some will choose to obey the Mosaic Law, while others will not.
No parents instruct to their children for the purpose of showing them how bad they are at following their instructions, but rather they give instructions to their children for their own good in order to teach them how to rightly live and how to be like them, and this is that much more true for our Heavenly Father (Deuteronomy 6:24, 10:12-13). Nowhere does the Bible say that all the Mosaic Law does is expose the desperate condition of man's heart, but rather it was given to teach us how to walk in God's way (Psalms 103:7).
You ignore the New Testament, rejecting what Paul and the writer to the Hebrews had to say.
The Psalms express an extremely positive attitude towards the Mosaic Law, such as with David repeatedly saying that he loved it and delighted in obeying it, so if we consider the Psalms to be Scripture and to therefore express a correct attitude towards the Mosaic Law, then we will share it, as Paul did (Romans 7:22). For example, according to Psalms 1:1-2, blessed are those who delight in the Law of the Lord and who meditate on it day and night, and we can't uphold the truth of these words as Scripture while not allowing them to shape our attitude towards to Mosaic Law. So it is not that I ignore the NT, but that I interpret the NT as though its authors considered the Psalms to be Scripture, and as though they were not in opposition to Christ and his Gospel.
By all means, live by the law. Just remember if you break one commandment, you break them all. And it's not a matter of outward observance. You can disobey the Law in your heart yet be outwardly perfect - just like a Pharisee. The letter kills, the Spirit gives life. The law is intended to lead us to Christ. If you are still bound by the Law, you are living as if you have yet to come to Christ. That has to be the most miserable existence, bound by rules you cannot keep and missing out on God's best, the law of the Spirit of Life in Christ Jesus.
If we beak any law and become a lawbreaker, then we need to repent and return to obedience to the Mosaic Law in accordance with what James 2:1-11 was encouraging them to do.
In Exodus 20:6, God wanted His people to love Him and obey His commandments, so obedience to the Mosaic Law has always been a matter of the heart.
God is not in disagreement with Himself about which laws we should follow, so the Law of Christ is the same as the Law of the Spirit and the Law of the Father, which was given to Moses, which is why Christ spent his ministry teaching his followers to obey, and why the Spirit has the role of leading us to obey it (Ezekiel 36:26-27).
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 Mosaic Law brings us to Christ because it teaches us how to know him, or in other words, how to have a relationship with him. It is absurd to suggest that those who are bond by what Christ taught have yet to come to him and that the way to come to Christ is by refusing to follow what he taught.
Do you believe that with God nothing is impossible...except obeying Him?
I've been studying God's word for 50 years. I reject the notion that Christians are under the Law of Moses. I spent the first years of my Christian life in the military. There sure was no sabbath observance possible then. According to the Law, I should have been taken out and stoned to death. I'm glad that I'm not subject to any law except the Law of the Spirit of Life in Christ.
That poor attitude towards the Mosaic Law is incompatible with the attitude towards it that David expressed in the Psalms, which means that you are denying that the Psalms are Scripture.
