And he said, behold now, I have taken upon me to speak unto
 the Lord (See Gill on Genesis 18:27): 
 Peradventure there shall be twenty found there;
 wouldest thou destroy it, such a number being in it; or, wouldest thou spare it for their sakes? 
 and he said, I will not destroy [it] for twenty's sake;
 if there were no more in it, I would spare it for their sake.