Genesis 18:31-33

And he said, “Now behold, I have decided to speak to the Lord [again]. Suppose [only] twenty [righteous people] are found there?” And the Lord said, “I will not destroy it for the sake of the twenty.” Then Abraham said, “Oh may the Lord not be angry [with me], and I will speak only this once; suppose ten [righteous people] are found there?” And He said, “I will not destroy it for the sake of the ten.” As soon as He had finished speaking with Abraham the LORD departed, and Abraham returned to his own place.