'My Lord the King' in the Bible

And David arose afterward and went out of the cave, and cried after Saul, saying, My lord the king! And Saul looked behind him. And David bowed his face to the earth and prostrated himself.

And now, please let my lord the king hear the words of his servant. If Jehovah has stirred you up against me, let Him accept an offering. But if it is the sons of men, they are cursed before Jehovah. For they have driven me out today from joining myself with the inheritance of Jehovah, saying, Go, serve other gods.

And David said to Achish, But what have I done? And what have you found in your servant so long as I have been with you to this day, that I may not go fight against the enemies of my lord the king?