Jews born before 70 A.D. and Jews born after 70 A.D. have never been or will ever be able to keep the entire Law of Moses, except for the one and only Jew who is our Lord and Savior, Yeshua HaMashiach. Both Jews and Gentiles who believe in Him have died to the law through the body of Christ. We therefore serve in the new way of the Spirit, not in the old way of the written code (Rom 7:1-6).
[1] Or do you not know, brothers--for I am speaking to those who know the law--that the law is binding on a person only as long as he lives? [2] For a married woman is bound by law to her husband while he lives, but if her husband dies she is released from the law of marriage. [3] Accordingly, she will be called an adulteress if she lives with another man while her husband is alive. But if her husband dies she is free from that law, and if she marries another man she is not an adulteress. [4] Likewise, my brothers, you also have died to the law through the body of Christ, so that you may belong to another, to him who has been raised from the dead, in order that we may bear fruit for God. [5] For while we were living in the flesh, our sinful passions, aroused by the law, were at work in our members to bear fruit for death. [6] But now we are released from the law, having died to that which held us captive, so that we serve in the new way of the Spirit and not in the old way of the written code.
One more point to add to this
People often mix cause and effect when it comes to
Hebrews 11.
God command all of us now to cease from our works and trust in Jesus's finished work for our salvation. We show our faith in him by
obeying exactly what he commanded us, and we are credited with salvation.
God commanded Noah to build an ark because a flood is coming. Noah showed his faith in God by likewise,
obeying exactly what he commanded, and he was credited with salvation
For the rest of the OT after the Law of Moses, God commanded all the Jews to circumcise their children (
Genesis 17), keep the Law, and sacrifice an animal every time they sinned. The Jews in the OT showed their faith in God by likewise,
obeying exactly what he commanded, and they were credited with salvation.
To give a counter-example, imagine if a Jew during the era of Leviticus were to ever tell the High priest and God, "
I am going to cease from my works and trust in Jesus's finished work at the cross for my salvation", I am not going to circumcise my male kids, keep the Law or sacrifice an animal".
If he were to do that, will he be saved? The answer is no, because those were not God's commandments for the OT Jews, as they are for us NOW. (I recall a similar scenario from the Choose your Own Adventure book "The Forbidden Castle")
None of us were saved by our own works. All of us obeyed what God commanded
in faith, during each period of time, and we are saved by that faith.