Jeremiah 3:18 - Joseph Benson’s Commentary on the Old and New Testaments

In those days the house of Judah, &c. Judah and Israel shall be happily united; the enmity that was between them shall be taken away, and they shall walk one with another, in a friendly manner, in the ways of God. This implies their being incorporated in one body, by one spirit, under Christ their head, and that without distinction of nations. This reunion of Israel and Judah, and their joint participation of the blessings of the Messiah's kingdom, is elsewhere foretold. See the margin. And they shall come together out of the land of the north Namely, out of their captivity; to the land that I have given them That is, the land of Canaan. Both Assyria and Chaldea fell into the hands of Cyrus, and his proclamation extended to all the Jews in all his dominions. And therefore we have reason to think that many of the house of Israel came with those of Judah out of the land of the north; though at first there returned but forty-two thousand, of whom we have an account, Ezra 2., yet Josephus saith, (Antiq., lib. 11. cap. 4,) that some years after, under Darius, Zerubbabel went and fetched up above four million of souls to the land that was given for an inheritance to their fathers. And we never read of such animosities and enmities between Israel and Judah as had been formerly. And the happy coalescence between Israel and Judah in Canaan was a type of their union, and that of Jews and Gentiles in the gospel church, when, all enmities being slain, they should become one flock under one shepherd. It may also be implied in these words, as many commentators think is expressly declared in many other passages of the ancient prophets, that in the latter days the Jews and Israelites, after their conversion to Christianity, shall actually return from their several dispersions to dwell, as a nation, in their own land.