They Will Be My People, and I Will Be Their God
This installment should be read with Part IV, as it continues directly from that post.
Something is said at the end of Jeremiah’s promise to “write the law on their hearts.” “I will be their God, and they shall be my people.” This is the effect of the former promise. This phrase has rich OT covenantal meaning that Jeremiah is drawing upon here. It means many things. Sometimes it means something similar to what it says here. That is, to be God’s people is to have a heart to know that he is the LORD. (This actually combines the “law on the heart” with “knowing the Lord” which we will look at next time). Part of what this also meant was to repent when you broke his law. “I will give them a heart to know that I am the LORD, and they shall be my people and I will be their God, for they shall return to me with their whole heart” (Jer 24:7). Repentance is a “turning” from sin back towards God. So the point is, when God becomes a person’s God in the new covenant, even when they disobey, they always return to him. This was not true in the old covenant, for many did not return to the LORD at all even though they were in covenant with God.
When God becomes your God in this way, you must obey him. Jeremiah said earlier in his book, “This command I gave them: ‘Obey my voice, and I will be your God, and you shall be my people’” (Jer 7:23; cf. Jer 11:4). Here, “they did not obey or incline their ear, but walked in their own counsel and evil hearts” (24). They didn’t want to obey God, even though they were in covenant with him. This is exactly why Jeremiah and Ezekiel say of the new covenant “I will give them one heart, and a new spirit … remov[ing] the heart of stone … that they may walk in my statutes and keep my rules and obey them. And they shall be my people, and I will be their God” (Ezek 11:19-20).
Part of being their God meant that he had delivered them from slavery. “I will take you to be my people, and I will be your God, and you shall know that I am the LORD your God, who has brought you out from under the burdens of the Egyptians’” (Ex 6:7). This deliverance was not only from (slavery) but to (the land). “Behold, I will gather them from all the countries to which I drove them in my anger and my wrath and in great indignation. I will bring them back to this place, and I will make them dwell in safety. And they shall be my people, and I will be their God” (Jer 32:37-38). This deliverance also included deliverance from sin. “You shall dwell in the land that I gave to your fathers, and you shall be my people, and I will be your God. And I will deliver you from all your uncleannesses” (Ezek 36:28-29). “I will bring them to dwell in the midst of Jerusalem. And they shall be my people, and I will be their God, in faithfulness and in righteousness” (Zech 8:8).
God delivers and saves and is to be obeyed because he is king. God said that he dwelt among them as their king. But a curious prophecy says that there will be more one day. “I will make my dwelling among you, and my soul shall not abhor you. And I will walk among you and will be your God, and you shall be my people. I am the LORD your God, who brought you out of the land of Egypt, that you should not be their slaves” (Lev 26:11-13). We can see then that something in the new covenant includes the LORD walking around. It is talking about the Lord Jesus. He will be their God through his new covenant.
What is important to take away from this post is that the phrase “I will be their God” was used in the old covenant. However, all of the people in that covenant did not have the law written on their heart, and thus the meaning implicit in this phrase in the old covenant was not carried out to completion. God actually divorced his people (Jer 3:1-8) and called them “Not My People” (Hos 1:9) after their rebellion. What is new about the new covenant in this regard must therefore be that all of the people in the new covenant have the law written on their hearts and God will truly be their God and God will truly fulfill, through Christ, these promises to them. For that is what the text says. Next time we will look at what it means to “know the Lord,” where we will see something very similar to what we have seen in these last two posts.
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 These things have an objective nature to them on the cross and a subjective nature to them when a person is supernaturally changed into a new creation.