And when he sits on the throne of his kingdom, he shall write for himself in a book a copy of this law, approved by the Levitical priests.
Deuteronomy 17:18

A king (and by extension, all leaders) should make a habit of continually reading and studying Torah throughout his life. Continually studying and *keeping* Torah cultivates humility and a fear of God, vital qualities in a leader.
#deuteronomy 17:18-20