Deuteronomy 17:17

When you have come to the land which the LORD your God gives you, and possess it and dwell in it, and say, “I will set a king over me, like all the nations that are around me,”

you shall surely set him whom the LORD your God chooses as king over yourselves. You shall set as king over you one from among your brothers. You may not put a foreigner over you, who is not your brother.

Only he shall not multiply horses to himself, nor cause the people to return to Egypt, to the end that he may multiply horses; because the LORD has said to you, “You shall not go back that way again.”

It shall be, when he sits on the throne of his kingdom, that he shall write himself a copy of this law in a book, out of that which is before the Levitical priests.

It shall be with him, and he shall read from it all the days of his life, that he may learn to fear the LORD his God, to keep all the words of this law and these statutes, to do them;

that his heart not be lifted up above his brothers, and that he not turn away from the commandment to the right hand, or to the left, to the end that he may prolong his days in his kingdom, he and his children, in the middle of Israel.