Deuteronomy 17:15-20

15you shall surely set a king over you whom the Lord your God chooses, one 1from among your 2countrymen you shall set as king over yourselves; you may not put a foreigner over yourselves who is not your 3countryman. 164Moreover, he shall not multiply horses for himself, nor shall he 5cause the people to return to Egypt to multiply horses, since 6the Lord has said to you, ‘You shall never again return that way.’ 177He shall not multiply wives for himself, 8or else his heart will turn away; nor shall he greatly increase silver and gold for himself.

18“Now it shall come about when he sits on the throne of his kingdom, he shall write for himself a copy of this law on a scroll 910in the presence of the Levitical priests. 19It shall be with him and he shall read it 11all the days of his life, that he may learn to fear the Lord his God, 12by carefully observing all the words of this law and these statutes, 20that his heart may not be lifted up above his 13countrymen 14and that he may not turn aside from the commandment, to the right or the left, so that he and his sons may continue long in his kingdom in the midst of Israel.