Deuteronomy 17:18-20

18When he takes the throne of his kingdom, he is to write for himself on a scroll a copy of this law, taken from that of the Levitical priests.

19It is to be with him, and he is to read it all the days of his life so that he may learn to revere the Lord his God and follow carefully all the words of this law and these decrees

20and not consider himself better than his fellow Israelites and turn from the law to the right or to the left. Then he and his descendants will reign a long time over his kingdom in Israel.