Deuteronomy 17:14-15

The King 14When 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,” 15be sure to appoint over you a king the LORD your God chooses. He must be from among your fellow Israelites. Do not place a foreigner over you, one who is not an Israelite.