Followers of Christ repeat Jesus' words "this cup is the new covenant" every time they observe the Lord's Supper. All over the world, local churches include the words new covenant in their names. But if you ask most Christians the question, "What is the new covenant?" you get about as many answers as the number of people you ask. What, then, is the new covenant? What is new about it? How is it fulfilled in Christ?
WHAT IS THE NEW COVENANT?
The foretelling of the new covenant in Jeremiah 31:31–34 begins in this way:
Behold, the days are coming, declares the LORD, when I will make a new covenant with the house of Israel and the house of Judah.
To understand this prophecy properly, we should ask how it fits with other Old Testament expectations for the future. The opening words "the days are coming" (v. 31) may appear rather vague to you and me, but the immediate context of this prophecy helps us see that Jeremiah's words were actually rather precise.
The prediction of a new covenant is part of a larger segment of the book of Jeremiah that extends from 30:1 through 31:40. This section is often called the Book of Restoration because it gives several descriptions of Israel's hardships during the exile and the blessings that were to come after the exile. The expression "the days are coming" also appears in 30:3, where it is explicitly associated with God's promise, "I will bring them back to the land that I gave to their fathers, and they shall take possession of it."
So, the expression "the days are coming" in 31:31 also refers to the time when the exile would be finished and God's people would return to the Promised Land. Isaiah 54:10, as well as Ezekiel 34:25 and 37:26, describe this covenant as a "covenant of peace." From the perspective of Old Testament prophecy, God would establish this covenant at the end of Israel's exile with the arrival of the Messiah and the worldwide kingdom of God.
HOW IS THE NEW COVENANT NEW?
There is so much confusion over what makes the new covenant "new" that we have to be careful not to go to extremes. On the one hand, many Christians have taken the expression new covenant to mean that it is entirely new, or "brand new," as we often put it. However, the word new translates the Hebrew term châdash, which does not mean "utterly new," as passages like Isaiah 61:4; Ezekiel 36:26; and Job 29:20 make clear. Rather, it means "renewed," "renovated," "rebuilt," or "refreshed." In other words, God did not promise an entirely new covenant in Jeremiah 31.
On the other hand, many Christians have also minimized what is "new" about the new covenant to the point that they see very little dierence between it and the old covenant. In contrast with this outlook, Jeremiah's prophecy actually focuses much attention on one of the main ways the new covenant will be different. As God put it in Jeremiah 31:32, the new covenant "will not be like the covenant I made with their forefathers when I took them by the hand to lead them out of Egypt."
Jeremiah's prophecy focuses on four features of the new covenant that make it different from the covenant that God made with Israel through Moses. First, the new covenant cannot be broken. In Jeremiah 31:32, God described the covenant with Moses as "my covenant that they broke." Generation after generation, the people of Israel so flagrantly violated the law of Moses that God eventually sent them into exile under the tyranny of evil nations and the false gods they served. The promised new covenant, however, would be different because it could never be broken like the covenant through Moses was. But how would this be possible? How would God ensure that the new covenant would never be broken?
The answer comes in our second point of difference between the old and new covenants, which is that the new covenant will entail the thorough transformation of God's people into His faithful servants. As God put it in Jeremiah 31:33, "I will put my law within them, and I will write it on their hearts." Rather than setting aside His commandments, God promised to transform His people so that they would wholeheartedly obey His commands. This kind of inward transformation was not something that had never happened before. Passages like Deuteronomy 10:16 and Jeremiah 4:4 called the people of Israel to move beyond their outward association with God's covenants to saving faith by circumcising their hearts and writing God's law on their hearts. Every man, woman, and child in Old Testament history who had saving faith like Abraham did had the law written on their hearts. So, how would the transformation of the new covenant be different from what had already taken place here and there throughout the Old Testament?
The answer, and our third point of difference, is that the inward transformation of the new covenant would include each person in covenant with God. As Jeremiah 31:34 puts it, "And no longer shall each one teach his neighbor and each his brother, saying, 'Know the Lord,' for they shall all know me, from the least of them to the greatest." Many people in Old Testament Israel knew God, but so many did not know Him that the nation as a whole broke Moses' covenant and fell under the judgment of exile. By contrast, God promised that every person in the new covenant, "from the least of them to the greatest," would have saving knowledge of Him. And what would be the result of this saving grace shown to every person in the new covenant?
The result is our fourth point of difference: the wondrous expectation that the sins of God's people will be forgiven forever. As we read in Jeremiah 31:34, "For I will forgive their iniquity, and I will remember their sin no more." Throughout the Old Testament, animal sacrifices made it possible for God's people to experience temporary relief from the judgment of God. By contrast, the new covenant would bring the permanent, eternal forgiveness of sins. It is no wonder, then, that Jeremiah's prophecy about a new covenant was cherished by the faithful in Israel. They longed for the day when their covenant relationship with God would be renewed. They looked forward to the time when all of God's people would be transformed into faithful servants and their sins forgiven forever.
HOW IS THE NEW COVENANT FULFILLED IN CHRIST?
The New Testament plainly teaches in many places that the new covenant of Jeremiah 31 is fulfilled in Christ. Yet, it is obvious that Jesus has not yet fulfilled every facet of this passage. For instance, none of us is perfectly conformed to the law of God in this life. We also know that there are plenty who are counted among God's new covenant people who have never received saving grace. The New Testament teaches us to call each other to know the Lord and to pray for the forgiveness of our sins day after day.
How can this be true if Jesus fulfills Jeremiah's prophecy? The New Testament explains that Jesus fulfills the expectations of a new covenant in the three stages of His messianic kingdom.
First, the inauguration of the new covenant came with Christ's first advent. In this stage of history, Christ fulfilled many—but not all—of the expectations of the new covenant. In His own service to God, Christ fulfilled the requirements of the moral law and paid the penalty for our disobedience by dying on the cross. As a result, everyone who trusts in Christ for salvation is justified and eternally forgiven of sin in the judgment of God's heavenly court. This is the wondrous truth that Jesus emphasized when He said to His disciples, "This cup is the new covenant in my blood, which is poured out for you" (Luke 22:20).
Second, what we may call the continuation of the new covenant age extends throughout church history as Christ rules from heaven until all of His enemies are put under His feet. During this time, many more—but still not all—of the expectations of the new covenant are fulfilled as the gospel spreads around the world. In Hebrews 9:15, we read that "Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance." As the One who rose to the right hand of the Father, Jesus serves as the mediator of the new covenant. As our new covenant mediator, Jesus ensures that His followers have access to the Father and that we receive His sustaining grace.
Finally, the new covenant age will reach its consummation in Christ's kingdom at His second advent. At this time, every promise associated with the new covenant will be fulfilled. All of God's people throughout the ages will be perfected in faithful service to God. And more than this, we will see the results of our eternal forgiveness in Christ, the "new heavens and earth" (Rev. 21:1) when God will make "everything new" (21:5).
It is no wonder, then, that Christ's followers love to speak of the new covenant. From the time of Christ's earthly ministry, God's people have enjoyed many blessings as a result of this new covenant. And we live every day of our lives with the eager expectation that when Christ returns in glory, we will enjoy the fullness of this new covenant forever.