The Locus Classicus of the New Covenant
Then we arrive at the prophecy about the New covenant (Jer. 31:31-34). The verses are immediately followed by a Divine guarantee of future fulfillment (Jer. 31:35-37). So it behooves us to look at it carefully:
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.” – Jeremiah 31:31-34
As verse 34 plainly says, the New covenant is a covenant of redemption! None of the other covenants of God have redemption built in to them. Because of this, they all ultimately rely on the New covenant to be fulfilled. The New covenant pictures a definitive act of God.
The fact that the New covenant brings redemption is central to a right understanding of the interplay of God’s covenantal Creation Project.
Now I know that as soon as one reads this text the temptation is to turn to the Book of Hebrews and to conclude that it is fulfilled in the Church. But I want my reader to refrain from turning the pages to the right and to stay with Jeremiah and the prophetic context of which he is a part, and let us see how things I am trying to unfold in this book. The Old Testament has the right to be heard by itself first.
The promise of the New covenant which will bind once more the divided tribes of Israel is prefaced by the refrain “the days are coming.” (Jer. 31:31): a phrase most often found in this book (15 times). It can refer to either imminent prophecy, say of the Babylonian captivity (e.g. Jer.7:32-34. Cf. Isa.39:6), or of impending doom (e.g. Jer.9:25; 48:12; 49:2). But in those places where righteousness and salvation are in view, the context is unwaveringly a “New covenant” eschatological context. We have seen that in Jeremiah 23:5-7 the expectation of the coming “Branch” who will bring in righteousness. The same may be said of the great messianic passage still to come in Jeremiah 33:14-16. The expression is used in Jeremiah 30:3 in connection with a return which will include the raising up of David (30:9). In Jeremiah 31:27 God promises to build up the nation once more, and while this could be viewed as referring to the return from exile, it seems more in keeping with the New covenant promises that it is in such close proximity to. Since the New covenant deals with salvation and renewal, one will often find kingdom prophecy where “the days are coming” is found (e.g. Amos 9:13).
As verse 32 declares, this “New” covenant is not a repristination of the old Mosaic covenant. Rather, as 31:33-34 state, this coming covenant works inwardly, just as was promised by Moses in Deuteronomy 30:6, “And the LORD your God will circumcise your heart and the heart of your descendants, to love the LORD your God with all your heart and with all your soul, that you may live.” Ezekiel prophesied the same thing in Ezekiel 11:19-29 and 36:26-27. The New covenant is the guarantee of transformation to conformity with the outcome of God’s purpose.
The coming New covenant is, I believe, one and the same with the coming Servant who will be made a redemptive and restorative covenant for the people (as we saw in Isa. 42:5 and 49:8). Because the stated intention of the Redeemer is to restore the fortunes of a united Israel (e.g. Isa. 45:14-17; Jer. 3:13-18; Ezek. 37:11-26), the first function of the New covenant is to facilitate that intention.
The New covenant is the redemptive covenant. It contains within it the elements of reconciliation and renewal for sinners and for their sin-cursed world. For this reason I shall, from now on, often be referring to covenant passages of salvation and reclamation as “New covenant passages.” The land and seed aspects of the Abrahamic covenant (including the Seed); the kingdom promise in the Davidic covenant, and the hope of a restored priesthood held out in the covenant with Phinehas all find their paths to realization in and through the New covenant. Even, arguably the Noahic covenant, with its inclusion of the natural world within its prescriptions, is “fulfilled” in the New covenant.
This approach to the biblical covenants goes against those understandings where the Abrahamic covenant is viewed as the greatest of the covenants. For although the national and international parts of God’s plan are captured in the pledges made to Abraham, Isaac and Jacob, the way to their coming to fruition is blocked until the sin of humanity is dealt with. It is the New covenant in Christ which unblocks the path to fulfillment by bringing reconciliation. All the other Divine covenants are reinvigorated by their combined association with the New covenant.
 Not to be confused with the extra-biblical “covenant of redemption” taught in covenant theology where at least two of the Persons within the Holy Trinity covenanted together before time to save the elect. Such a “covenant” is never spoken about in Scripture and is inferred on the back of a certain theology. To me, the idea that there was a covenant within the Godhead is absurd. Covenants are only necessary when at least one of the parties is, for whatever reason, potentially unreliable.
Karl Barth raised a different objection to a pre-creational covenant when he asserted that such an idea was “mythology, for which there is no place in a right understanding of the doctrine of the Trinity.” Barth complained that, “God is one God. If He is thought of as the supreme and finally the only subject, He is the one subject.” If one introduces a pact between the Persons of the Godhead, a measure of dualism is introduced as well; a dualism which such a covenant inevitably creates (Ibid). Further, because it necessarily includes man, such a pact within the Trinity violates the unity of the pre-temporal divine economy. See his full discussion in Karl Barth, Church Dogmatics (Peabody, MA: Hendricksen, 2010), IV.1, 65-66.
Michael Horton notes some of Barth’s objections in his The Christian Faith: A Systematic Theology for Pilgrims on the Way (Grand Rapids: Zondervan, 2011), 303, but I find his response to be wide of the mark.
 Michael D. Williams, Far As The Curse Is Found: The Covenant Story of Redemption (Phillipsburg, NJ: P&R, 2005), 215. Williams believes the phrases “everlasting covenant” and “covenant of peace” in Isaiah 54:8-10; 61:8; Ezek. 34:25; 37:24-28 (along with Jer. 32:37-41; 50:5) are synonyms for the New covenant.
 See Hebrews 8:10-12. This is the longest quotation of an OT passage by a NT author. In my view the automatic link with the Church is made too hastily.