Ez. 37:15-23 describes a reunited nation with all twelve tribes coming together in unity. Verse 22: “I will make them a single nation in the land, on the hills of Israel, and one king shall be king of them all. Never again shall they be two nations, and never again shall they be divided into two kingdoms.” I wonder how well that prophesy went – did the nation really come together from that time forward? Have they not had civil war since? Erza did make some mention of all the tribes coming together to return to the land. Sometime I’ll have to re-read the genealogies in Ezra, Nehemiah, & Chronicles (ugh) to see if he included the northern tribes. If memory serves, it seems he focused mainly on the Levites, so I’m not sure his texts will answer that question.