Law was given to Moses after 430 years promise of Israel was given to Abraham. Because the purpose of law is know the sin. If there is no commandment or law one cannot say this is sin. Apart from law sin is there but not taken into account. Now sin is lawlessness. Law has temporary mission. Law shows us our sin and points us to Christ. Love is the fulfillment of law so that there may be righteousness for everyone who believes. Christ is the end of the law.So in everything do to others as you would have them do to you this sums up the law and the prophets. This golden rule is 100% law and the prophets in one sentence. Jesus said decalogue or ten commandments are summarized into two commandments which the greatest commandment love the Lord your God with all your heart mind soul and strength. And the next is as you love yourself love your neighbour. On these two commandments hang all the law and the prophets. Law is for the unsaved because if they do not have the law they stumble. Law is like tutor but when we are owner we do not need law. Hagar is law but Abraham would not have needed. Sarah is grace and promise. Rabbi Hillel is asked to tell the whole law in one sentence he told what is hateful to you do not do to anyone else. This is the whole law and the rest is the commentary. Go and learn it.Christians believe in salvation by grace through faith in Jesus but not through observing the law. We are not saved by good works but we are saved to do good works. Christianity is not all rules or no rules but an experience with Jesus and Holy Spirit. Jesus Christ replaced law with himself and his words. Covenant always comes with commandments or laws. Repentance to commandment is not important repentance to Jesus Christ is important.