The Law that Jesus came not to abolish is the Law of the Gospel
The Law that Jesus came not to abolish, from which shall pass not one jot or one tittle, is the Law of the Gospel, which is the true Law of God. But Jesus Christ abolished many commandments of the Old Testament (Matthew 5:31-48, Matthew 12:1-8, John 5:8-11, John 5:16-18, John 8:3-11 and the whole context of the Gospel).
The Gospel says: "Think not that I am come to destroy the law, or the prophets.... one jot or one tittle shall in no wise pass from the law" (Matthew5:17-20).
In these words are based many religions to tell us that Jesus Christ came not to abolish the commandments of the Old Testament, but that is a mistake because these gospel's words do not refer to the law of the Old Testament, because Jesus Christ abolished many commandments of the Old Testament, as we see in Matthew 5:31-48 and other parts of the Gospel.
The words of Jesus Christ in this famous verse (Matthew 5:17), which tells us that He did not come to abolish the Law and the Prophets, refers to the true Law of God, which is the Law that Jesus Christ himself taught us in the Gospel. Jesus Christ teaches that the law and the prophets that He did not come to abolish is the following:
"Allthings whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets" (Matthew 7: 12).
Therefore, this is the law that God gave to Israel because Jesus Christ himself says that "this is the law and the prophets". This is the law that remains in effect, that Jesus Christ came not to abolish ("Think not that I came to destroy the Law or the Prophets"). And of this law did pass "not one jot not one tittle", of the Law that Jesus Christ teaches us in the Gospel and that is the true Law that God gave to Moses.
Now I also remember the Law of Jesus Christ expressed in commandments, as the Gospel teaches:
"And behold, one came to him and said, Teacher, what good thing shall I do, that I may have eternal life? And he said unto him, Why askest thou me concerning that which is good? One there is who is good: but if thou wouldest enter into life, keep the commandments. He saith unto him, Which? And Jesus said, Thou shalt not kill, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness, Honor thy father and mother; and, Thou shalt love thy neighbor as thyself. The young man saith unto him, All these things have I observed: what lack I yet? Jesus said unto him, If thou wouldest be perfect, go, sell that which thou hast, and give to the poor, and thou shalt have treasure in heaven: and come, follow me. But when the young man heard the saying, he went away sorrowful; for he was one that had great possessions" (Matthew 19: 16-22
And this law and these commandments are in effect for all peoples.
However, no one is under the laws of the Old Testament that were abolished by Jesus Christ, because those laws were not true Law of God. We are all under the Law and the commandments of Christ, which are the only true Law of God.