The Torah instructs the King of Israel to carry a Torah at all times…so that his heart be not haughty over his brothers and so that he swerve not from what is commanded right or left, in order that he may long endure in his kingship…When it comes to observing the commandments, the monarch receives no special dispensation. This helps to ensure, explains the Malbim, that his heart will not become haughty over his brothers. The more a king’s life resembles the life of everyone else, the easier it is for him to remain humble and for his subjects to remain connected to him. This strengthens the monarchy and the possibility that the king will long endure in his kingship.