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.
Read halakhic rulings (Jewish law) on Jeremiah 31:1: and classical halakhic sources.