'My Lord the King' in the Bible

And Joab answered, May Jehovah add to His people a hundred times, but my lord the king, are they not all my lord's servants? Why then does my lord require this thing? Why will he be a cause of trespass to Israel?

And Ornan said to David, Take for yourself, and let my lord the king do what is good in his eyes. Lo, I give the oxen for burnt offerings, and the threshing instruments for wood, and the wheat for the food offering. I give it all.