Is there really a New Testament (New Covenant) ? If so how is it different?
Yes, there is a New Testament. It came about because of some of the Old Testament prophets that prophesied about a new covenant that God was making with his people. The words Testament and covenant refer to the same thing.
In Jeremiah 31:31-34, God declares that he is making a new covenant with his people, the house of Israel and Judah. He charges that they broke the old covenant. Old covenant refers to the covenant that God made with Moses on Mount Sinai. This is the covenant from which all of the Old Testament laws originate.
There have been several covenants throughout Scripture that God makes with different people. One of the things we must realize about a covenant is that it has an initiator and a beneficiary. The covenant is in place as long as the initiator continues to agree to it, changes it, or dies. Since God is the initiator of all the covenants, they are still in place.
Some of them become obsolete as new covenants are made. This is what has happened to the old covenant as far as Christians, who follow the new covenant, are concerned. This doesn’t mean that the old covenant does not have any value. Indeed, the Old Testament, or old covenant, is still attached to Christian Bibles.
Back to Jeremiah 31:31-34. God declares that he is making a new covenant with Israel. In the New Testament, the claim can be made that God’s people, the true Israel, includes everyone who follows the new covenant through Jesus Christ.
God claims that part of the new covenant will be him putting his laws within them and write them on their hearts (Jeremiah 31:33). This is fulfilled for those who follow the new covenant through following Jesus. He fulfilled Old Testament law in himself and those who follow his teachings and commandments fulfill the law through obedience to his Spirit.
Jesus taught about internalizing Old Testament law, using many examples from the Ten Commandments in his Sermon on the Mount. He would start by saying, “You have heard it said…” Then he would follow that with a much harder teaching requiring not only outward or behavioral obedience but internal obedience.
Jeremiah follows by recording God saying that he will be their God and they will be his people (Jeremiah 31:33). Jesus does this in the new covenant because he is the second member of the Trinity, God himself come to humanity. And those who follow him are his people. He unites in himself both believing Jews and believing Gentile (Ephesians 2:11-22; Romans 9-11).
God then declares that no one will have to teach his neighbor about the Lord because they will know the Lord from the least of them to the greatest (Jeremiah 31:34). This is best demonstrated in the new covenant by the pouring out of the Holy Spirit (Acts 2:1-11).
On the Day of Pentecost, the Holy Spirit was poured out on the least and the greatest. In the old covenant, the Holy Spirit came upon people who would fulfill service in the three offices of Israel, prophets, priests, and kings. They were anointed as a sign that the Holy Spirit was upon them for service in these three offices.
But the amazing thing about the new covenant and the pouring out of the Holy Spirit on all flesh (Joel 2:28 and following) is that every believer in Jesus in the New Testament receives the Holy Spirit as he dwells in them. No longer does he choose individuals and come upon them, but now he dwells in followers of Jesus.
Because the Holy Spirit dwells in believers, they know God, the third member of the Trinity. They also know Jesus, the second member of the Trinity. So they will all know God from the least of them to the greatest.
Finally as part of this prophecy from Jeremiah, God says that he will forgive their iniquity and remember their sins no more (Jeremiah 31:34). This is fulfilled through Jesus’ forgiveness of the sin of those who believe in his name. Because Jesus is God, he is literally fulfilling this prophecy for all who believe in him.
Another way that the new covenant or New Testament is different from the Old Testament or old covenant is that it shows the messianic prophecies coming true through the person and work of Jesus Christ. Parts of the New Testament go to great length to show that he is the Messiah who fulfills all of the Old Testament prophecies about him.
Throughout the Old Testament there are many prophecies about a Servant who will come in God’s name and restore Israel. This individual in Isaiah is known as the suffering Servant. There are psalms about him as well. And there are many prophecies in the prophetic books.
He is called the Lord’s Anointed One, also known as the Messiah. Scriptures about him are littered throughout the Old Testament. Jesus comes and fulfills all of these prophecies, showing that he is this Anointed One, the one who ultimately fulfills all of these Scriptures.
The new covenant is administered by him to the people of God. So the New Testament is all about Jesus, the Messiah. The New Testament, or new covenant, is different from the old for these reasons. But it presents a sort of new era or new realm, which Jesus calls the kingdom of God. It shows those who believe in Jesus how to live in this new covenant.