What would Plato be without Socrates, or Timothy without Paul, or Luther without Augustine, or Foucault without Nietzsche, or Bob without Woody, or Elvis, The Beatles, and every hair-spritzed glam rocker to follow them without the blues riff? Ask this and you get a sense of the architectonic influence that the book of Deuteronomy has over the prophet Jeremiah.

Unlike his Judahite predecessor Isaiah, Jeremiah drank deeply of the theological vintage of the book of Deuteronomy. That is not to say that Isaiah was not familiar with the ancient law book; his corpus of work is thick with Deuteronomic language and imagery: the holiness of God, concern for the disenfranchised, the synergy between personal holiness and cultic worship. But for Jeremiah, it is different. For him, Deuteronomy is an immovable force, a covenantal mass that holds a wholly central position around which his entire prophetic agenda satellites. 

For some ancient historians, the rediscovery in 622 B.C. of the covenant code hidden away in what was likely a Temple genizah proves too convenient an explanation to be taken at face value. In this view, the putative discovery belies what is, in fact, a new codification of a particular political tradition that happened to be in the ascendancy at the time.  Such theories, while perhaps interesting, are entirely speculative and destabilizing to the actual biblical account. 

Over the course of its life since canonization, the book of Jeremiah has earned a reputation for complaint for righteous grievance that has resulted in one new word in the English lexicon, "jeremiad" as well as the general neglect of his work in the contemporary church. The exceptions, of course, would be the comforting passages of Jeremiah 31-33, the "shalom of the city" passage of (Jer 29:7), and the favorite of Bible verse embroiderers, Jer 29:13, a verse about the restoration from exile. 

This is regrettable because Jeremiah plays such a central role in the biblical canon. His thorough use of Deuteronomy acts like a relay device in redemptive history, revisiting and reapplying the covenant of Moses with such universality and detail that his prophecy can be used as a guide to the eschaton by later prophets (Ezra 1:1; Dan 9:2; cf. Matt 16:14). His temple ministry is the model for Jesus' own cleansing of the temple in the Synoptic Gospels (Matt 21:12-27 ; Mark 11:12-25; cf. Jer 7:1-26; Jer 24:1-10). There is a golden braid of Deuteronomic thought which can be traced from Jeremiah to the two groups of the restoration community, including those who returned (Zerubbabel, Ezra, Nehemiah) and those who stayed (Daniel, Esther), and finally to Jesus himself. 

That could be a good sermon series, dear expositors.

How must Jeremiah have understood Deuteronomy? Imagine you were a constitutional lawyer, and a new clause of the Constitution is discovered, one that fills in some previous lacuna of the document and further connects ideas which you had always thought to be unsourced. This new discovery would occupy your thoughts, reframing everything you knew before. Now imagine an exhaustive review of the government was called for by the president in light of this discovery, and you were involved in the  investigation. It would be kind of a big deal.

For this reason, the life and prophecies of Jeremiah might be described as an extended exploration of the theology of Deuteronomy in the late pre-exilic period. No doubt due to the rediscovery of the law book and King Josiah's subsequent reforms (2 Kings 22-23), the covenant looms large in the imagination of the prophet who is called to escort Jerusalem through her final days before the exile. Deuteronomic language pervades the prophet's sermons and prayers, including his call narrative, which borrows language from Deut 18:15-19 (Jer 1:5-12).[1] The Temple Sermon of Jeremiah 7 illustrates his concern for the "sojourner, the orphan, and the widow" (Jer 7:6), a common Deuteronomic refrain (Deut 18:6; 23:8; 24:17; 27:19). The allegations against the Jerusalemite leadership are heightened in light of the purity of the central sanctuary  which bears the Lord's name (Jer 7:14; or Shiloh, Jer 7:12), and their lack of singular obedience to the voice of the Lord (Jer 7:28; Deut 8:20; 13:18; 15:5; 21:18; 27:10; 28:1, 2, 15, 45, 62; 30:8, 10).

Perhaps more than any other part Jeremiah's theology of the heart is strongly evocative of the same in Deuteronomy, particularly as it is expressed in the text known as the Shema (Deut 6:4-9) which calls for a love that is whole-heartedly devoted to the Lord. In light of the whole-hearted devotion, Jeremiah draws the peoples' attention to their own great deficit of heart. Their hearts are depicted as "deceitful above all and desparately sick" (Jer 17:9). Much like the wicked and exiled northern kingdom, Judah's repentance and faith is shallow (Jer 3:8-10), a reference most likely to the quick dismantling of Josiah's reforms by his successors. Jeremiah borrows the image of a circumcised heart (Jer 4:4; Deut 10:16; 30:6) to explain how covenantal faithfulness must be a matter of the person's inner parts and not merely the outer body. Unless they repent sincerely and "wash [their] evil hearts" (4:10-14), they will suffer judgment.

Furthermore, the heart problem facing Judah can only be remedied by the Lord's provision of a new heart, a heart of faithfulness, which will come about as a result of exile. After the righteous remnant have suffered in exile, the Lord will restore them through repentance. This repentance will not be insincere, but rather it will derive from a "new heart" given to them by the Lord (Jer 24:7). With this new heart, they will be equipped to seek him with their "whole hearts" (Jer 24:7; 29:11-14; cf. Ezek 36:26), and this new heart will have the law of the Lord written upon it that it might never be forgotten (Jer 31:31-34). For Jeremiah, this new heart, the one the people need to worship the Lord, is a blessing of the New Covenant for them and for their children (Jer 32:38-39).

In these passages, the New Covenant is presented as a future event, one that will be established in the due course of redemptive history, following the exile's sanctifying effect on the righteous remnant. The reader must be careful not to confuse the historia salutis with the ordo salutis, a common theological error which leads the reader to miss the true efficacy of the New Covenant blessings for the Old Testament believer. In terms of ordo salutis the Apostle Paul goes to great lengths to show how the faith that is reckoned as righteousness for Abraham is the same faith that is reckoned as righteousness for those acquainted with the risen Christ (Romans 4:9-25; Gal 3:7-14) as does the author of the letter to the Hebrews (Hebrews 11). In terms of the historia salutis, however, the New Covenant can only be finally established in Jesus' blood (Luke 22:20) and the outpouring of the Spirit at Pentecost (Gal 3:13-14).  The course of redemptive history must be fulfilled.

This is why Jeremiah's call to repentance becomes a central theme for the exilic community that hopes to trigger the restoration of the kingdom. For instance, Daniel reads Jeremiah and is immediately compelled to repent on behalf of the people (Dan 9:1-19). John the Baptist offers a baptism of the repentance in the Judean desert, with which "all of Judea" participates (Matt 3:5; Mark 1:4-5; Luke 3:3) including Jesus himself (Matt 3:13-15). This passage in Matthew 3 raises several interesting questions. Throughout the section, Jesus is clearly being depicted as a sort of true Israel, and he claims this for himself elsewhere (John 15:1-16). He is the one called out of Egypt (Matt 2:15), he is the "beloved Son" of God (Matt 3:17), and he is the one who successfully resists temptation in the wilderness (Matt 4:1-2). So why does he submit himself to John's baptism of repentance? After all, he has nothing for which to repent and John has no standing to administer such a baptism to the sinless seed of the woman, which is exactly John's complaint when Jesus appears on the banks of the Jordan ("you should be baptizing me!" Matt 3:14). To put it another way, how does Jesus' baptism "fulfill all righteousness" as he claims (Matt 3:15)?

I suspect the answer might be found in the substitutionary nature of the ministry of Jesus. In this passage, we have been given the privilege to see how Christ provides both the grounds and model of our own repentance as the people of God. Jesus himself is the righteous remnant the prophets anticipate. He is the righteous Israel who longs for God in Deut 30:1-2 and Jer 29:13, and as such he alone can trigger actual restoration in a way that Daniel, Zerubbabel, and Nehemiah could not. Indeed, he is the righteous Adam Israel needed.  Just as he will sinlessly die for the sins of his people, so he also sinlessly undergoes the baptism of repentance for them. Just as the former is substitutionary, perhaps the latter is also. Those who are in him by faith are united with the "remnant" and, as a result of their union with him, become recipients of the restored kingdom. His heart provides the wellspring from which all regenerate hearts receive their life. 

In this way, Jeremiah's promise of a new heart is fulfilled in Christ. Anyone who is united with him receives a new heart as a result, and this covenant blessing is not for mere children of the flesh but for children of the promise, first to ethnic Israel, but then by God's grace to the world (Rom 9:6-8).

Notes:

[1] Lundbom provides a useful list of exact wording from Deuteronomy appearing in Jeremiah. Lundbom, Deuteronomy, pp. 41-42. See also, Driver, Deuteronomy, xcii.