Deuteronomy 17:14-18

14“When you come to the land that Adonai your God is giving you, possess it and dwell in it, and you say, ‘I will set a king over me, like all the nations around me,’

15you will indeed set over yourselves a king, whom Adonai your God chooses. One from among your brothers will be appointed as king over you—you may not put a foreigner over you, who is not your brother.

16Only he should not multiply horses for himself or make the people return to Egypt to multiply horses, because Adonai has said to you, “You must never go back that way again.”

17Nor should he multiply wives for himself, so that his heart does not turn aside, nor multiply much silver and gold for himself.

18“Now when he sits on the throne of his kingdom, he is to write for himself a copy of this Torah on a scroll, from what is before the Levitical kohanim.