Rambam, Laws of Kings and Wars 2:6
Just as the Torah has granted him great honor and obligated everyone to revere him; so, too, has it commanded him to be lowly and empty at heart, as Psalms 109:22 states: 'My heart is a void within me.' Nor should he treat Israel with overbearing haughtiness. For Deuteronomy 17:20 describes how 'he should not lift up his heart above his brothers.'
He should be gracious and merciful to the small and the great, involving himself in their good and welfare. He should protect the honor of even the humblest of men.
When he speaks to the people as a community, he should speak gently, as I Chronicles 28:2 states 'Listen my brothers and my people....' Similarly, I Kings 12:7 states 'If today, you will be a servant to these people....'
He should always conduct himself with great humility. There is none greater than Moses, our teacher. Yet, he said Exodus 16:8: 'What are we? Your complaints are not against us.' He should bear the nation's difficulties, burdens, complaints, and anger as a nurse carries an infant.
Psalms 78:71 refers to a king as a shepherd: 'to pasture, Jacob, His nation.' The prophets have described the behavior of a shepherd (Isaiah 40:11): 'He shall pasture His flock like a shepherd, He shall gather the lambs with His arm and carry them in His bosom."
In other words, humility is not the enemy of self-esteem, but of pride.
-Byron R. Sherwin, Jewish Ethical Values (2015), p.93
Humility is not a question of thinking less of yourself. It is a question of thinking of yourself less.
-Larry Bossidy