This might come as news to some of you, but the New Covenant really is new.

For the law was given through Moses; grace and truth came through Jesus Christ.

John 1:17

I've heard many testimonies of Muslims who have found the Qur'an pointing back to Moses and Jesus Christ as prophets, and so have read the Old and New Testaments. They found that the Qur'an pointed to the Bible, but the Bible does not point to the Qur'an. But notice that the Old Covenant does a similar thing with the New Covenant:

The Lord your God will raise up for you a prophet like me from among you, from your brothers—it is to him you shall listen— just as you desired of the Lord your God at Horeb on the day of the assembly, when you said, ‘Let me not hear again the voice of the Lord my God or see this great fire any more, lest I die.’ And the Lord said to me, ‘They are right in what they have spoken. I will raise up for them a prophet like you from among their brothers. And I will put my words in his mouth, and he shall speak to them all that I command him. And whoever will not listen to my words that he shall speak in my name, I myself will require it of him.

Deuteronomy 18:15-19

He was still speaking when, behold, a bright cloud overshadowed them, and a voice from the cloud said, “This is my beloved Son, with whom I am well pleased; listen to him.”

Matthew 17:5

If you love me, you will keep my commandments.

John 14:15

Now, I'm not suggesting that we only need the New Testament. Far from it! We need the Old Testament in order to understand the New Testament. But, the Law of Moses points to the Law of Christ. The Law of Christ, however, does not point back to the Law of Moses.

Look at the Letter to the Hebrews. It was written in the time of greatest persecution to encourage believers to not turn back to the Old Covenant, but to press ahead in the New Covenant. It says:

Now if perfection had been attainable through the Levitical priesthood (for under it the people received the law), what further need would there have been for another priest to arise after the order of Melchizedek, rather than one named after the order of Aaron? For when there is a change in the priesthood, there is necessarily a change in the law as well.

Hebrews 7:11, 12

Consider the contrast between the two Covenants in this description:

For you have not come to what may be touched, a blazing fire and darkness and gloom and a tempest and the sound of a trumpet and a voice whose words made the hearers beg that no further messages be spoken to them. For they could not endure the order that was given, “If even a beast touches the mountain, it shall be stoned.” Indeed, so terrifying was the sight that Moses said, “I tremble with fear.” But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering, and to the assembly of the firstborn who are enrolled in heaven, and to God, the judge of all, and to the spirits of the righteous made perfect, and to Jesus, the mediator of a new covenant, and to the sprinkled blood that speaks a better word than the blood of Abel.

Hebrews 12:18-24

If you are in the New Covenant, you cannot try to live by the Old Covenant. That only leads to confusion, guilt, and legalism. Don't miss what Paul said:

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.

Romans 7:6