'Lord' in the Bible

But Joab said, "May Yahweh add to the people a hundred times what they are! Are they not, O my lord the king, all of them the king's servants? Why does my lord seek this? Why would he bring guilt to Israel?"

And Ornan said to David, "Take [it] to yourself; let my lord the king do what [is] good in his eyes. See, I give the cattle for the burnt offerings and threshing sledges for the wood and wheat for the grain offering--I give [it] all."