Genesis 18:29-31 New American Standard Bible (NASB)

29. He spoke to Him yet again and said, "Suppose forty are found there?" And He said, "I will not do it on account of the forty."

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."

31. And he said, "Now behold, I have ventured to speak to the Lord; suppose twenty are found there?" And He said, "I will not destroy it on account of the twenty."

Genesis 18