Genesis 18:20-25

And the Lord said, "The cry of Sodom and Gomorah has become great, and their sin is grave. I will go down and see whether their actions altogether match their cries that have reached me. (i.e. if things are as bad as they sound) If not, I will know..." And Abraham approached [God] and said, "Will You destroy the righteous with the wicked? Perhaps there are fifty righteous men in the midst of the city. Will You even destroy and not forgive the place for the sake of the fifty righteous men who are in its midst? Far be it from You to do a thing such as this, to put to death the righteous with the wicked so that the righteous should be like the wicked. Far be it from You! Will the Judge of the entire earth not perform justice?" [Translation by Hillel and Panim]