I have written before on the subject of the conversion of the Jews (here, here, and here), so this post will rehash some material from those earlier posts. However, it has been several years, so I feel a need to revisit the question, and from a different text.
"Thus says the Lord: Behold, I will restore the fortunes of the tents of Jacob and have compassion on his dwellings; the city shall be rebuilt on its mound, and the palace shall stand where it used to be. Out of them shall come songs of thanksgiving, and the voices of those who celebrate. I will multiply them, and they shall not be few; I will make them honored, and they shall not be small. Their children shall be as they were of old, and their congregation shall be established before Me, and I will punish all who oppress them. Their prince shall be one of themselves; their ruler shall come out from their midst; I will make Him draw near, and He shall approach Me, for who would dare of himself to approach Me, declares the Lord?: And you shall be My people, and I will be your God" (Jeremiah 30:18-22).
The first part of these verses could be taken to refer to the restoration of Judah after the exile in Babylon, the same events we see described in Ezra and Nehemiah. However, that is just a launching point, used typologically for events we have yet to see either in Israel or among the Jewish diaspora.
While modern Jews are mostly secular, often even agnostic or atheist, the people described in this passage are expressing thanks and celebrating God, because they are a people who are established in faithfulness before their God.
The description of their prince is especially amazing to me, because it is couched in the same language as the davidic, messianic prince. Compare the words of Deuteronomy 18:15: "The Lord your God will raise for you a prophet like me [I. e., Moses] from among you, from your brothers...," and its explicit fulfillment in Acts 7:37. This is none other than the Lord Jesus Christ, the Son of David: "He will be great and will be called the Son of the Most High. And the Lord God will give to Him the throne of His father David, and He will reign over the house of Jacob forever, and of His kingdom there will be no end" (Luke 1:32-33).
Jeremiah is prophesying to Israel a hope, not merely of the restoration to the land after exile in Babylon, but restoration to the covenantal relationship with her God that she had eschewed in idolatry. He remained faithful, though she was faithless (II Timothy 2:13). As he says to Israel: "You shall be My people, and I will be your God" (Jeremiah 30:22), just as He first said to them in Exodus: "I am the Lord, and I will bring you out from under the burdens of the Egyptians, and I will deliver you from slavery to them, and I will redeem you with an outstretched arm and with great acts of judgment [against them]. I will take you to be My people, and I will be your God, who has brought you out from under the burdens of the Egyptians" (Exodus 6:6-7)
