'My Lord the King' in the Bible

David also arose afterward, and went out of the cave, and cried after Saul, saying, "My lord the king!" When Saul looked behind him, David bowed with his face to the earth, and did obeisance.

Now therefore, please let my lord the king hear the words of his servant. If it is so that Yahweh has stirred you up against me, let him accept an offering. But if it is the children of men, they are cursed before Yahweh; for they have driven me out this day that I shouldn't cling to Yahweh's inheritance, saying, 'Go, serve other gods!'

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