A Christian's relationship with God is not through Moses, but through Jesus. Faith and grace (Romans 6:15) are the basis of a relationship with God in this age. The Law was supposed to lead to Christ. Galatians 3:24 (NIV), “So the law was our guardian until Christ came that we might be justified by faith.”
In Romans 7:4 (NIV) we read, “So, my brothers and sisters, you also died to the law through the body of Christ that you might belong to another, to him who was raised from the dead, in order that we might bear fruit for God.” The change that happened with Christ and Church is not unusual in Biblical history. The first basis for a relationship between man and God was the Adamic Covenant, then followed the Abrahamic Covenant, the Mosaic Covenant and the Samuel Covenant for Kings.
Referring to Jews who believed in Jesus, Apostle Paul says in Colossians 2:14-17 (NIV), “having canceled the charge of our legal indebtedness, which stood against us and condemned us; he has taken it away, nailing it to the cross. And having disarmed the powers and authorities, he made a public spectacle of them, triumphing over them by the cross.”
No, Christians are not under the Law of Moses. Christians have a higher law (standard) of love that motivates them not to respond with “eye for eye” and “tooth for tooth” but to bless their enemies and to do good to those who prosecute them. Matthew 5:38, 39 “You have heard that it was said, ‘Eye for eye, and tooth for tooth.’ But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek also.”
Galatians 5:14, “For the entire law is fulfilled in keeping this one command: “Love your neighbor as yourself.”
After a person has accepted Christ’s sacrifice for his sins, he is to keep the commandments of God in the “spirit of the law.” Paul wrote, "That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit," Romans 8:4.