While in Egypt the Hebrews were under the Law of the Pharaohs.
Having been taken out of Egypt and God declaring them to be a Nation, they now needed a rule of Law to live by. At Mount Sinai, God gives them His Holy Standard known as The Law or the Mosaic Law or Covenant (sometimes referred to as the Old Covenant today). The Jews include the first five books of the Bible in the Law, or the Torah as they call it.
This rule of law was only given to the Jews; not to any other nation.
The reason for this was to set the Jewish people apart from the other nations in order for them to be Holy and to be His alone.
The people agreed to this new Law.
Exodus 19: 8
Then all the people answered together and said, “All that the LORD has spoken we will do.” So Moses brought back the words of the people to the LORD.
The law in and of itself is good.
Romans 7:12
Therefore the law is holy, and the commandment holy and just and good.
However, the one thing it could not give them, or us, is the power needed to fulfil its demands.
Hebrews 7: 18-19
For on the one hand there is an annulling of the former commandment because of its weakness and unprofitableness, 19 for the law made nothing perfect; on the other hand, there is the bringing in of a better hope, through which we draw near to God.
As a result of this deficiency, the need for the sacrificial system was introduced.
In addition, we also read that the Law gives sin it’s power.
1 Corinthians 15:56
The sting of death is sin, and the strength of sin is the law.
The result of all this? No one is justified before God by the Law.
Galatians 3:11-12
But that no one is justified by the law in the sight of God is evident, for “the just shall live by faith.” 12 Yet the law is not of faith, but “the man who does them shall live by them.”
Galatians 2:21
“I do not set aside the grace of God; for if righteousness comes through the law, then Christ died in vain”.
Then why the Law?
Galatians 3:19-25
What purpose then does the law serve? It was added because of transgressions, till the Seed should come to whom the promise was made; and it was appointed through angels by the hand of a mediator. 20 Now a mediator does not mediate for one only, but God is one. 21 Is the law then against the promises of God? Certainly not! For if there had been a law given which could have given life, truly righteousness would have been by the law. 22 But the Scripture has confined all under sin, that the promise by faith in Jesus Christ might be given to those who believe. 23 But before faith came, we were kept under guard by the law, kept for the faith which would afterward be revealed. 24 Therefore the law was our tutor to bring us to Christ, that we might be justified by faith. 25 But after faith has come, we are no longer under a tutor.
The breaking of the Law did not annul the previous Covenant God made with the nation of Israel, that is, the Abrahamic Covenant, as that was an unconditional covenant. (That’s why today even though they reject Jesus and break the Law the land is still theirs).
God told them He would give them a new, and better, Covenant.
Jeremiah 31:31
“Behold, the days are coming, says the LORD, when I will make a new covenant with the house of Israel and with the house of Judah … .
The Lord Jesus Christ is the mediator of this new Covenant and the end of the law so that there may be righteousness for everyone who believes.
Hebrews 9:15
And for this reason He is the Mediator of the new covenant, by means of death, for the redemption of the transgressions under the first covenant, that those who are called may receive the promise of the eternal inheritance.
Romans 10:4
and all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ.
Jewish and Gentile believers follow the Law of Christ today as led by the Holy Spirit.