Genesis 18:23-25

Genesis 18:23-25. And said, Wilt thou also destroy the righteous with the wicked? Peradventure there be fifty righteous within the city: wilt thou also destroy and not spare the place for the fifty righteous that are therein? That be far from thee to do after this manner, to slay the righteous with the wicked: and that the righteous should be as the wicked, that be far from thee: Shall not the Judge of all the earth do right?

Abraham bases his argument upon the justice of God; and when a man dares to do that, it is mighty pleading, for, depend upon it, God will never do an unjust thing. If thou darest to plead his righteousness, his infallible justice, thou pleadest most powerfully.