Deuteronomy 17:14-15
14
The King
When you enter the land the Lord your God is giving you and have taken possession of it and settled in it, and you say, “Let us set a king over us like all the nations around us,”
15 be sure to appoint over you the king the Lord your God chooses. He must be from among your own brothers. Do not place a foreigner over you, one who is not a brother Israelite.