A messianic prophecy
The New Covenant
The promise
In the heart of his book of comfort, Jeremiah announces the most far-reaching promise in the Old Testament: Behold, the days come, saith the Lord, that I will make a new covenant with the house of Israel and with the house of Judah. It would not be like the old covenant made at Sinai, which the people had broken again and again. This one would be different in its very nature.
God describes what would be new about it. I will put my law in their inward parts, and write it in their hearts, so that obedience would flow from within rather than being imposed from without. They shall all know me, from the least to the greatest, so that knowledge of God would no longer belong to a few but to all his people. And most wonderful of all, I will forgive their iniquity, and I will remember their sin no more.
This was a staggering promise to a people whose failure under the old covenant had led to exile. God was pledging not to patch up the old arrangement but to make a new one, grounded in an inward transformation and a full and final forgiveness. The whole hope of Israel came to rest on this promise of a covenant that could not be broken because God himself would write it on the heart.
The measure of how new this covenant is lies in that final clause: I will remember their sin no more. Under the old covenant the sacrifices were a yearly reminder of sins never finally dealt with. Jeremiah promises the opposite, a forgiveness so complete that God himself chooses to remember the sin no longer. It is not that God forgets, but that he refuses to hold the sin against his people ever again, a mercy the old order could only foreshadow.
“Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah: Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD: But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more.”Jeremiah 31:31-34
The fulfillment
On the night before he died, Jesus took the cup at the last supper and said, This cup is the new testament in my blood, which is shed for you. The word testament is the word for covenant, and Jesus was declaring that the new covenant Jeremiah had promised was now being established, sealed not in the blood of animals but in his own blood, poured out for the forgiveness of sins.
The letter to the Hebrews takes up Jeremiah's promise at length and quotes it in full, applying every clause to Christ. It argues that by speaking of a new covenant, God had made the first one old, and that Jesus is the mediator of a better covenant, established on better promises. Through his once-for-all sacrifice, the law is written on the heart by the Spirit, all his people know God, and their sins are remembered no more.
So the deepest promise of the prophets, a covenant of inward transformation and complete forgiveness, is fulfilled in Jesus. What Jeremiah foresaw from a distance, Jesus inaugurated in the upper room and secured on the cross, and every time his people share the cup they proclaim the new covenant in his blood.
Hebrews presses the logic of Jeremiah's word to its conclusion. If God promised a new covenant, then he had already declared the first one obsolete and passing away. And if sins are remembered no more, then no further sacrifice for sin is needed, for the one offering of Christ has done what the endless offerings of the old order never could. The whole argument rests on taking Jeremiah's ancient promise as fulfilled, precisely and finally, in Jesus.
“For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah: Not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they continued not in my covenant, and I regarded them not, saith the Lord. For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people: And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest. For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more.”Hebrews 8:8-12
Why it matters
This prophecy reaches the very heart of the gospel, because it promises the two things every soul most needs: a new heart and a clean slate. The law written on the heart means that God does not merely command obedience from outside but works it within by his Spirit. The sin remembered no more means that forgiveness is not partial or provisional but full and final.
That is why the new covenant is such good news for those who have failed. The old covenant exposed sin but could not cure the heart; the new covenant, sealed in the blood of Jesus, both forgives the sin and changes the sinner from within. It rests not on our faithfulness, which fails, but on his, which does not.
To trust Christ is to enter this new covenant, to receive the forgiveness he purchased and the new heart he gives, and to know God personally rather than at a distance. Every time his people take the cup, they remember that the deepest promise of the prophets has come true, and that God has done for us what we could never do for ourselves.
This is the covenant every anxious conscience longs for. It does not ask us to keep ourselves in God's favor by a faithfulness that always fails; it rests on the faithfulness of Christ, who wrote the covenant in his own blood. The law on the heart means God works within us what he requires of us, and the sin remembered no more means the past is truly past. That is freedom, and it is the gift of the new covenant.
Every time the Lord's people gather at his table, they proclaim this fulfillment afresh. The cup is the new covenant in his blood, and to drink it is to remember that the deepest promise of the prophets has come true, that our sins are remembered no more and his law is written on our hearts. The new covenant is not a doctrine to be admired from a distance but a gift to be received, again and again, at the table of the Lord.
Questions people ask
What is the new covenant that Jeremiah promised?
Jeremiah foretold a covenant unlike the one Israel broke, in which God writes his law on the heart, gives everyone knowledge of himself, and forgives sin completely so as to remember it no more. It answers the heart-problem the old covenant exposed but could not fix. The New Testament presents this promise as fulfilled in Jesus, whose death establishes the forgiveness and inward renewal Jeremiah described.
How did Jesus establish the new covenant?
At the Last Supper Jesus took the cup and spoke of it as the new covenant in his blood, tying his coming death to Jeremiah's promise. Hebrews quotes Jeremiah in full and argues that Christ's single offering secures the forgiveness and heart-written law the prophet foretold, making the old covenant obsolete. So the new covenant is founded on Jesus' sacrifice, which provides complete pardon and inward transformation.
What makes the new covenant different from the old one?
The old covenant, made at Sinai, was broken again and again because it was imposed from outside. Jeremiah promised a new covenant that God would write on the heart, so that obedience flows from within, in which all his people would know him and their sins would be remembered no more. Jesus established it in his blood at the last supper, and Hebrews applies Jeremiah's whole promise to him.