Genesis 18:30-32
18:30 Then Abraham said, “May the Lord not be angry so that I may speak! What if thirty are found there?” He replied, “I will not do it if I find thirty there.”
18:31 Abraham said, “Since I have undertaken to speak to the Lord, what if only twenty are found there?” He replied, “I will not destroy it for the sake of the twenty.”
18:32 Finally Abraham said, “May the Lord not be angry so that I may speak just once more. What if ten are found there?” He replied, “I will not destroy it for the sake of the ten.”