The new covenant is spoken about first in the book of Jeremiah. The old covenant  that God had established with His people required obedience to the Old Testament  Mosaic law. Because the wages of sin is death (Romans  6:23), the law required that people perform rituals and sacrifices in order  to please God and remain in His grace. The prophet Jeremiah predicted that there  would be a time when God would make a new covenant with the nation of  Israel.

“‘The day will come,’ says the Lord, ‘when I will make a new  covenant with the people of Israel and Judah. . . . But this is the new covenant  I will make with the people of Israel on that day,’ says the Lord. ‘I will put  my law in their minds, and I will write them on their hearts. I will be their  God, and they will be my people'” (Jeremiah  31:31, 33).  Jesus Christ came to fulfill the law of Moses (Matthew  5:17) and create a new covenant between God and His people. The old covenant  was written in stone, but the new covenant is written on our hearts, made  possible only by faith in Christ, who shed His own blood to atone for the sins  of the world. Luke 22:20 says, “After supper, [Jesus] took another cup of wine and said, ‘This wine is  the token of God’s new covenant to save you – an agreement sealed with the blood  I will pour out for you.'”

Now that we are under the new covenant, we  are not under the penalty of the law. We are now given the opportunity to  receive salvation as a free gift (Ephesians  2:8-9). Through the life-giving Holy Spirit who lives in all believers (Romans 8:9-11), we can now  share in the inheritance of Christ and enjoy a permanent, unbroken relationship  with God. Hebrews  9:15 declares, “For this reason Christ is the mediator of a new covenant,  that those who are called may receive the promised eternal inheritance—now that  He has died as a ransom to set them free from the sins committed under the first  covenant.”