Deuteronomy 17:18-20

18“When he sits on the throne as king, he must copy for himself this body of instruction on a scroll in the presence of the Levitical priests.

19He must always keep that copy with him and read it daily as long as he lives. That way he will learn to fear the Lord his God by obeying all the terms of these instructions and decrees.

20This regular reading will prevent him from becoming proud and acting as if he is above his fellow citizens. It will also prevent him from turning away from these commands in the smallest way. And it will ensure that he and his descendants will reign for many generations in Israel.