Reference for Jeremiah 31:1

בָּעֵ֤ת הַהִיא֙ נְאֻם־יְהוָ֔ה אֶֽהְיֶה֙ לֵֽאלֹהִ֔ים לְכֹ֖ל מִשְׁפְּח֣וֹת יִשְׂרָאֵ֑ל וְהֵ֖מָּה יִֽהְיוּ־לִ֥י לְעָֽם׃ (ס)

In those days, the word of the LORD, I will be unto thee a God, for all families of Israel, and they will be unto me a people.

BDB