Genesis 18:30; Genesis 18:32

30 Then he said, "Oh may the Lord not be angry, and I shall speak; suppose thirty are found there?" And He said, "I will not do it if I find thirty there."

32 Then he said, "Oh may the Lord not be angry, and I shall speak only this once; suppose ten are found there?" And He said, "I will not destroy it on account of the ten."