Deuteronomy 17:14-15

14When thou art come unto the land which the LORD thy God giveth thee, and shalt possess it, and shalt dwell therein; and shalt say, I will set a king over me, like as all the nations that are round about me;

15thou shalt in any wise set him king over thee, whom the LORD thy God shall choose: one from among thy brethren shalt thou set king over thee: thou mayest not put a foreigner over thee, which is not thy brother.