What is the new covenant?

You have met the word already, whether or not anyone explained it. The two halves of your Bible are named after it: Old Testament and New Testament mean old covenant and new covenant. Christians say the word at communion and sing it in hymns. Few of them stop to define it.

A covenant is a binding relationship that God sets up by promise. It is not a contract between equals who bargain over terms. God declares what He will be to His people and what He requires of them, and then He seals the arrangement so it cannot be treated as loose talk. In Scripture that sealing is done with blood.

That is the language Jesus reached for on the night before He died.

Luke 22:20 (NKJV)

Likewise He also took the cup after supper, saying, “This cup is the new covenant in My blood, which is shed for you.”

Every man at that table knew what a covenant was, and knew that blood sealed it. The word that would have stopped them was new. Something was being replaced, and they had lived under the thing being replaced their whole lives.

The old covenant was sealed at the foot of a mountain. God brought Israel out of slavery in Egypt, gathered them at Sinai, gave them His law, and told them plainly what the arrangement would be: He would be their God, they would be His people, and this was how they were to live. Then Moses sealed it.

Exodus 24:8 (NKJV)

And Moses took the blood, sprinkled it on the people, and said, “This is the blood of the covenant which the LORD has made with you according to all these words.”

Attached to that covenant was a system of sacrifices. When an Israelite sinned he brought an animal to the priest, laid his hand on its head, and the animal died in his place. There was an offering every morning and every evening, and one every year for the whole nation.

Centuries of it. Then the writer of Hebrews looks back on the whole system and says this:

Hebrews 10:4 (NKJV)

For it is not possible that the blood of bulls and goats could take away sins.

Which sounds, at first, as though none of it mattered.

It mattered. God commanded those sacrifices, and the Israelite who brought one went home forgiven. What Hebrews denies is that the animal was the reason, because a goat is not the equal of a man. It could take his place at the altar. It could not take his place before God.

God was forgiving on the strength of a death still to come.

Hebrews 9:15 (NKJV)

And for this reason He is the Mediator of the new covenant, by means of death, for the redemption of the transgressions under the first covenant, that those who are called may receive the promise of the eternal inheritance.

The transgressions under the first covenant are the sins committed before Christ was born, and His death is what dealt with them. Abraham, David, and Isaiah were not saved by a different arrangement from the one that saves you. They were saved by the same blood, credited to them centuries before it was shed.

This is why Reformed Christians read the Bible as one book with one plan rather than two religions bound together. The framework has a name — covenant theology — and it means simply this: from the promise God made in the Garden after the Fall (Genesis 3:15), through the covenant cut with Abraham (Genesis 15), through the law given at Sinai, God has been unfolding one plan of salvation by grace.

The second thing true of the old sacrifices is that they never stopped.

Hebrews 10:11–14 (NKJV)

And every priest stands ministering daily and offering repeatedly the same sacrifices, which can never take away sins. But this Man, after He had offered one sacrifice for sins forever, sat down at the right hand of God, from that time waiting till His enemies are made His footstool. For by one offering He has perfected forever those who are being sanctified.

Every priest stands. He stands because there is nowhere in the tabernacle for him to sit. Exodus describes the furnishings in detail — the lampstand, the table, the altar, the basin — and no seat is among them. A priest whose work was finished would have needed one. He never sat, because the work never finished.

Then a Man offered one sacrifice and sat down.

None of this took God by surprise. Six hundred years before that supper, with Jerusalem sliding towards ruin, He announced through Jeremiah exactly what He intended to do.

Jeremiah 31:31–34 (NKJV)

Behold, the days are coming, says 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 that I took them by the hand to lead them out of the land of Egypt, My covenant which they broke, though I was a husband to them, says the LORD. But this is the covenant that I will make with the house of Israel after those days, says the LORD: I will put My law in their minds, and write it on their hearts; and I will be their God, and they shall be My people. No more shall every man teach his neighbor, and every man his brother, saying, “Know the LORD,” for they all shall know Me, from the least of them to the greatest of them, says the LORD. For I will forgive their iniquity, and their sin I will remember no more.

God says what went wrong, and it was not the law: “My covenant which they broke.” The commandments were never the problem. Stone can tell a man what is right; it cannot make him want it.

So if the first covenant broke because the people broke it, what stops this one going the same way?

God answers that in the first thing He promises: “I will put My law in their minds, and write it on their hearts.” The same law, no longer standing outside the man telling him what he owes, but inside him — and that writing is what changes what he wants. He does not wait for a willing heart and then write on it. He writes, and the willingness follows. That is why this covenant holds where the other broke: God supplies from His own side what He requires from ours.

A law written inside a man changes what he can know of God. “They all shall know Me, from the least of them to the greatest of them.” Under Moses, knowing God ran through a priesthood and a building. Now the least of them knows Him as truly as the high priest ever did.

Then the promise Jeremiah saves for the end: “I will forgive their iniquity, and their sin I will remember no more.” Not forgotten, since God knows everything that has ever happened, but never brought up against them again. Under the old covenant the offerings came round every year, and every year they brought the same sins back to mind. This covenant does not bring them back.

Every covenant needs a guarantor. Moses stood between God and Israel at Sinai. Hebrews puts Christ in that place now, “Mediator of a better covenant, which was established on better promises” (Hebrews 8:6). Better, because this Mediator does not die and leave the post empty, and because the blood that sealed the covenant was His own. Hebrews also names who it is for: “those who are called.” A covenant is a bond with a particular people, not an announcement made to the air.

That is what Jesus was holding when He lifted the cup. Israel had waited through exile, return, and long centuries of silence, and now a Man at a supper table spoke as though the waiting were over. It was. Within a day the blood that sealed the covenant had been shed. Your sin may still trouble you. It will not be raised against you. God has told you what He will do with it: “their sin I will remember no more.”