The primary focus of Jeremiah’s ministry was indeed Judah in the south. However, as we have already noted above, Jeremiah’s concern for the nation ultimately went beyond just Judah. This section (Jeremiah 3:12–18) ends with a vision of a reunited Israel, which includes people from both north and south. The Lord had after all made his covenant with the whole nation, not just with Judah. This concern for the northern tribes is seen also in the fact that Josiah tried to extend his reforms into the north (2 Kings 23:15–20; 2 Chronicles 35:16–19). So, it is not surprising that the Lord would call on his prophet to proclaim his words towards the north.
His message in Jeremiah 3:12–18 would have had deep significance for the exiled people of the northern tribes of Israel who were already living under the rule of the Assyrian empire after the fall of Samaria in 722 BC, but they would have been equally significant for the people of Judah who were about to experience their own exile. His call for the north to return to the Lord was meant to awaken a response from Judah. If return was still possible even for the exiled northern tribes, then it was possible for Judah.
12 Go, and proclaim these words toward the north, and say, “‘Return, faithless Israel,declares the LORD. I will not look on you in anger, for I am merciful,declares the LORD; I will not be angry forever.