Genesis 18:25

That be far from thee An exclamation of deprecation, like "God forbid," or the Lat. nefas tibi sit. LXX μηδαμῶς, Lat. absit a te. Cf. chap. Genesis 20:4, "Lord, wilt thou slay even a righteous nation?"

that so the righteous should be as the wicked This was one of the great problems of religious thought in ancient Israel. The Book of Job is devoted to the consideration of this mystery of human life. Under a Divine Government of the Universe, should the innocent be consumed in the same overthrow as the evil-doer? If the Israelite's sense of justice rebelled against the notion that suffering always implied sin, conversely it cherished the hope that the suffering of the innocent might vicariously be for the good of the community.

the Judge of all the earth A very remarkable declaration that Jehovah is supreme throughout the world. Whether or not the writer admitted the existence of other gods in other lands, he here asserts the complete sovereignty of Jehovah: cf. Genesis 6:1 ff., Genesis 8:21-22; Genesis 11:1-9. This is not monotheism, but it is the stage next before it. The "Judge" of a Semitic people was ruler, judge, and advocate. God does not judge after the sight of the eyes, or the hearing of the ears, but righteous judgement. Cf. Deuteronomy 32:4; Isaiah 11:3.

do right Lit. "do judgement." The Judge (shôphêt) will do judgement (mishpât). This is the foundation of a moral belief.

"Righteousness is one, whether in God or in man. It would be wrong in a human judge or ruler to condemn the righteous with the wicked, or destroy them indiscriminately … The fact that God is God does not withdraw Him and His actions from the sphere of moral judgement. Nothing would be right in God because He is God, which would not be right in Him were He man" (Davidson, Theology of O.T.p. 130). This is one great contrast between the Christian and the Mahommedan view of God.