At the same time, saith the LORD, will I be the God of all the families of Israel, and they shall be my people.
As in that chapter the restoration of Judah, so in this the restoration of Israel's ten tribes, is foretold.
At the same time - "in the latter days" (Jeremiah 30:24).
Will I be the God of - manifesting my special grace to (Genesis 17:7; Matthew 22:32; Revelation 21:3).
All ... Israel - not the exiles of the southern kingdom of Judah only, but also the northern kingdom of the ten tribes; and not merely Israel in general, but "all the families of Israel." Never yet fulfilled (Romans 11:26).