'My Lord the King' in the Bible

Then David got up afterward and went out of the cave and called after Saul, "My lord the king!" When Saul looked after him, David knelt down [with his] face to the ground and bowed down.

Then Saul recognized David's voice and said, "[Is] this your voice, my son David?" And David said, "[It is] my voice, my lord the king."

And so then, please let my lord the king listen to the words of his servant: If Yahweh has incited you against me, may he delight in an offering; but if {it is mortals}, [may] they be accursed {before} Yahweh, for they have driven me away today from sharing in the inheritance of Yahweh, saying, 'Go, serve other gods!'

Then David said to Achish, "But what have I done? And what have you found in your servant from the day that I {entered your service} until this day, that I should not go and fight against the enemies of my lord the king?"