In those days translates the same expression used in verse 16; it is equivalent to “At that time” in verse 17. It may not be natural to retain this phrase (so Good News Translation) if readers recognize readily that this is a continuation of the message from the previous verse.

The house of Judah is simply a way of saying “the people of Judah.” Die Bibel im heutigen Deutsch effectively uses a second person noun of address: “You people of Judah will unite with the people of Israel….” Note that in this example they would have to be “you.” This would link well with your fathers at the end of the verse.

The land of the north here includes both Assyria and Babylonia, reflecting the fall of Samaria in 722 B.C. and the fall of Jerusalem in 586 B.C. These were the lands to which Israel and Judah were carried into exile, hence “come from exile” (Good News Translation). But other translators may choose to retain from the land of the north and put the information concerning exile into a footnote.

Gave … for a heritage translates one verb in Hebrew, which Good News Translation and Die Bibel im heutigen Deutsch render “gave … as a permanent possession.” The verb is used in this same sense in 12.14.

Fathers here indicates “ancestors” (Good News Translation, Die Bibel im heutigen Deutsch), as in 2.5.

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on Jeremiah. (UBS Helps for Translators). New York: UBS, 2003. For this and other handbooks for translators see here .