Deu 17:18-20 NLT
18 "When he (Israel's King) sits on the throne as king, he must copy these laws on a scroll for himself in the presence of the Levitical priests.
19 He must always keep this copy of the law 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 this law.
20 This 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. This will ensure that he and his descendants will reign for many generations in Israel.