Genesis 18:26-28
26 The Lord said, “If I find fifty righteous people in the city of Sodom, I will spare the whole place for their sake.” 27 Then Abraham spoke up again: “Now that I have been so bold as to speak to the Lord, though I am nothing but dust and ashes, 28 what if the number of the righteous is five less than fifty? Will you destroy the whole city for lack of five people?”