Yes, and the covenant is in his blood, as the Scripture says in Hebrews 12 -".22 But ye are come --------
24. to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than [that of] Abel.
After the death of Jesus. Paul taught of the life and works of Jesus Christ and his teaching of a New Covenant
The promise of the New Covenant has been given to the remnant of the Jewish nation. For all intents and purposes the New Covenant has been received by the believers in Jesus Christ.
God
Jesus Christ, the Messiah of Israel.
Church of the New Covenant in Christ was created in 1975.
The word Testament means covenant. The Old Testament describes the old covenant God made. The New Testament describes the new covenant Gad made with humans through Christ Jesus. The Old Testament looks forward to Christ where as the New Testament looks back at the promises of Christ.
You could use the word "covenant" The Old Testament was the old covenant concerning the law and the New Testament is the new covenant which explains the Grace of God to mankind in sending His only begotten Son into the world to save sinners. The old covenant is no longer in force. Jesus Christ is the way, the truth, and the life. No one comes to the Father but through Him (Jesus Christ)
If you are talking about the New Jerusalem, that is Heavenly Jerusalem, all that enter are Christian all enter in under the new covenant that covenant between JESUS those with the Heavenly calling the 144,000. that covenant was instituted at the time of the last supper with his apostles who became Christian when they accepted the Christ as God's anointed son and began following his course in making disciples of the Christian Congregation. Remember, these apostles were once Jews, and followed the Jewish Law Covenant but that covenant became obsolete when Christ installed the New Covenant, and it was prophesied about in the book of Jeremiah.However, the Law covenant became in a sense "obsolete" when God announced by means of the prophet Jeremiah that there would be a new covenant. (Jer 31:31-34; Heb 8:13) In 33 C.E. the Law covenant was canceled on the basis of Christ's death on the torture stake (Col 2:14), the new covenant replacing it.---Heb 7:12; 9:15; Ac 2:1-4. Anyone who refuses to accept Jesus as God's son will not gain everlasting life.The new covenant is made operative by the shed blood (the sacrifice of the human life) of Jesus Christ, the value of which was presented to Jehovah after Jesus’ ascension to heaven. (Mt 26:28) When one is selected by God for the heavenly calling (Heb 3:1), God brings that one into His covenant over Christ’s sacrifice. (Ps 50:5; Heb 9:14, 15,26) Jesus Christ is the Mediator of the new covenant (Heb 8:6; 9:15) and is the primary Seed of Abraham. (Ga 3:16) By means of Jesus’ mediatorship of the new covenant, he assists those in the covenant to become part of the real seed of Abraham (Heb 2:16; Ga 3:29) through forgiveness of their sins. Jehovah declares them righteous.—Ro 5:1,2; 8:33; Heb 10:16,17. Read these scriptures in your Bible and you will understand the New Covenant.
Christianity started with Jesus Christ. Jesus came down from heaven from God the Father to reconcile sinners back to God. Since the time of Adam mankind has been alienated from God by sin. Jesus died on the cross to be the ultimate sacrifice for sin. Only persons who believe in Jesus Christ by faith can be saved from eternal damnation and be given eternal life. While on earth Jesus chose 12 disciples/apostles. These men were believers that Jesus was the Son of God and were trained by Him to carry on the work of Jesus to reconcile others to God. In the Old Testament, Jeremiah 31:31 it says," Behold, the days are coming, when I will make a new covenant with the house of Israel and with the house of Judah......" The old covenant ended and the new covenant began when Jesus Christ died on the cross and was resurrected three days later. The old covenant was the Law of Moses and was for the Jewish nation. The new covenant was to be a transition for the Jews to follow the Messiah and be directed by Him in a new way. They rejected Jesus as being the Messiah and have continued in the old covenant which is no covenant at all since Jesus died and was resurrected. God included the Gentile nations into the new covenant, which brings us to the Apostle Paul. The apostle Paul was picked by God the father and Jesus Christ in eternity past to be the Apostle to the Gentiles. (If you are not Jewish you are a Gentile). Paul traveled over much of the Roman Empire (A very large area) and preached about Jesus Christ being the Son of God and that faith in Him is necessary to be saved and have eternal life. Since that time generation upon generation has been passing on the "Good News" (Gospel) that Jesus Christ is the Savior of any who will believe in Him.
When Jesus the Christ was born on the earth to Mary in Bethlehem He was born a Jew from the tribe of Judah. Jesus followed the Law of Moses that was given to the Israeli people by God. Judaism was the Jew's true religion. Judaism and Christianity are closely related and it was Jesus Christ who was the founder of Christianity. He and the Father God in heaven gave this "New Covenant" to the Jewish people, and it became effective when Jesus died on the cross of Calvary and was resurrected the third day after. Sadly the Jewish people rejected Jesus the Christ as their Messiah, and so the Gentiles were offered the New Covenant. Prophecy tells us that after the Great Tribulation, which is still future, the Jewish people will accept Jesus as Savior and will also be included in the New Covenant.
Jesus Christ fulfills the covenant that God made with humanity. Acts 3:25 says "Ye are the children of the prophets, and of the covenant which God made with our fathers, saying unto Abraham, And in thy seed shall all the kindreds of the earth be blessed." The seed of Abraham is Jesus. Galatians 3:17 says that the covenant was confirmed before God in Christ. Hebrews Chapter 8 says a lot about God's covenant. Hebrews 12:24 says that Jesus is the mediator of the new covenant. Hebrews 13:20 mentions the covenant.
The New Covenant took effect the same minute that Jesus Christ died. The New Covenant erased the Death Penalty either by stoning or any other method invented by man. The New Covenant is based on Mercy and Forgiveness and 2nd Chances. Unfortunately 95% of the Jews rejected Jesus as the Messiah and son of God by asking the Roman Empire to kill Jesus. The Jews have until this day of the 21st Century innocent blood in their hands for asking the Romans to kill Jesus so the Jews are not God's people at all.