Many commentators believe that Jeremiah's revelation of the New Covenant was his greatest theological contribution. They view it as the high point of the book, the climax of the prophet's teaching.
"The prophecy of Jeremiah marks a watershed in Hebrew religious and cultic life. From this point onwards there is a significant divergence between what has obtained in the past and what will characterize the future religious observances of Israel."410
31:31 In the future the Lord would make a new covenant with all the Israelites, specifically the Israelites who had inhabited the Northern Kingdom and those who had inhabited the Southern Kingdom (cf. 32:40; Ezek. 37:26; Luke 22:20; 1 Cor. 11:25; 2 Cor. 3:6; Heb. 8:8-9:28).411
"The short passage which develops from the simple announcement in this verse is one of the most important in the book of Jeremiah. Indeed it represents one of the deepest insights in the whole OT."412
31:32 This New Covenant would be different from the Mosaic Covenant, which the Israelites consistently and inevitably broke in spite of Yahweh's faithful commitment to them. They had worshipped Baal (Heb. ba'al) even though Yahweh had been a faithful husband (Heb. ba'al) to them.
31:33 Instead of God's law being external to them, the Lord would write it on their heart (i.e., mind and will; cf. 17:1). He would do something for them that they could not do for themselves (cf. Deut. 30:5-6). Writing on the heart suggests the removal of written documents and merely human mediators. Having the Lord's word in the heart prevents sin and fosters obedience (cf. Deut. 11:18; Ps. 40:8; 119:11).
"It will become part of the nature of God's people; it will be instinctive. The core of the new covenant is God's gift of a new heart (cf. Ezek 36:25-27). Herein lies the sufficient motivation for obeying God's law."413
God would also enter into intimate relationship with His people as His covenant partners (cf. 7:23; 11:4; 24:7; 30:22; 31:1; 32:38; Deut. 31; Ezek. 11:20; 36:28). The old Mosaic Covenant being broken, a new relationship would begin.
"If the sheer grace of God's election of Israel as covenant partner was apparent in the first covenant making, how much more so in this promise following their history of unfaithfulness and rebellion (v 32)."414
Notice that Jeremiah revealed nothing about human responsibility under the New Covenant. That would come later with the teachings of Jesus Christ and the apostles.
31:34 All the Israelites, from the least to the greatest, would also know the Lord intimately, without having to be exhorted to do so.
"The verb knowhere probably carries its most profound connotation, the intimate personal knowledge which arises between two persons who are committed wholly to one another in a relationship that touches mind, emotion, and will. In such a relationship the past is forgiven and forgotten."415
They would know Him in this intimate way because He would forgive their sins and not bring them to memory or judgment any more. True forgiveness, in contrast to the covering of sin that the Old Covenant sacrifices provided, would make intimacy with God possible.
"The old covenant spoke of a great physical deliverance from Egypt through the blood of lambs and the power of God; the new covenant proclaims a great spiritual deliverance from sin and death through the efficacious blood of the Lamb of God and the power of God. The Passover Feast memorialized the first; the Lord's Supper memorializes the second."416
There are three basic views concerning the identity of the people with whom God would make this new covenant and when He would make it. One view is that God will make it with Israel alone when He resumes dealing with that nation as formerly, namely, in the Millennium (cf. Rom. 11). Another view is that God made it with the church alone, which advocates of this view (i.e., covenant theologians) say replaces Israel in God's plans, and he made it at the Cross. A third view is that God made it with Israel at the Cross, and the church somehow enters into its blessings.
I hold the third of these views. It seems to me that God made the New Covenant with Israel when Jesus Christ died on the cross (Luke 22:20). The church now operates under this covenant (1 Cor. 11:25; 2 Cor. 3:1-14; Heb. 8:8-12; 10:16-17).417However, Israel will enter into the blessings of this covenant, which God promised her, at the time of Israel's restoration, namely, at the second coming of Christ.418
This arrangement resembles one that is possible to set up in a Charitable Lead Unit Trust under the Internal Revenue Code of the United States. Suppose there was a vastly wealthy and generous philanthropist of the magnitude of a Bill Gates. As he prepared his will he bequeathed millions of dollars to various charitable causes that would benefit millions of people all over the world when he died. He also wrote into his will that when his only son reached the age of 21 he would inherit billions of dollars. When this man died, his son was only five years old, so for 16 years he did not enter into his father's inheritance. However as soon as the philanthropist died the millions of dollars he had bequeathed to charity went to work immediately to help many people.
This illustration shows how the church enters into the blessings of the New Covenant. When Christ established the Lord's Supper it was as though He notarized His will; it became official then. The will is the New Covenant. When He died His "estate"became available to those He chose to profit from it. Soon many people around the world, Jews and Gentiles in the church, began to benefit from the blessings of His death. However God's chosen people, His son Israel, will not enter into his unique inheritance until the appointed time, namely, the Millennium. Blessings for the church began almost immediately after Christ's death. Blessings for Israel will not begin until God's appointed time arrives.
Which blessings of the New Covenant does the church enjoy now and which are for Israel in the future? There are four promises in verses 33 and 34. The promise of having God's law written on the heart has been fulfilled to a limited extent. Christians do have an innate desire to please God because of the indwelling Holy Spirit's ministry, but we do not have the innate understanding of God's will that God promised here. Second, we have a unique covenant relationship with God as Christians, but it is not the same covenant relationship that God promised the Israelites here. Third, all Christians know the Lord to some degree of intimacy now, but we do not all have the depth of relationship with God that He promised the Israelites here. We still need teaching and teachers, but this will not be the case for Israel in the future. Fourth, Christians enjoy the complete forgiveness of sins, as the Israelites will in the future. So I would say we enjoy all these blessings to some extent, but not to the extent Israel will enjoy them in the future. We may enjoy the last promise just as the restored Israelites will. As the return from exile was a partial fulfillment of the promises of restoration, so the church's enjoyment of these blessings are only a partial fulfillment of what God promised Israel.419
The New Covenant is a branch of the Abrahamic Covenant. In the Abrahamic Covenant, God promised Abraham a piece of real estate for his descendants, an incalculable number of descendants, and blessing for his descendants and for all people through his descendants (Gen. 12:1-7; et al.). Deuteronomy 29-30, sometimes called the Palestinian Covenant, gave more information about the land God had promised to Abraham. The Davidic Covenant gave more information about God's promises regarding descendants (2 Sam. 7). The New Covenant revealed the particulars of the promised blessing (Jer. 31). Each of these later covenants relates to the Abrahamic Covenant organically; each is an outgrowth of it in the progress of revelation. In contrast, the Mosaic (Old) Covenant does not relate organically but "was added"(Gal. 3:19) to explain how the Israelites could maximize the benefits God had promised in the Abrahamic Covenant. Consequently when God terminated the Old Covenant it did not eliminate anything He had promised in the Abrahamic, "Palestinian,"Davidic, or New Covenants.