“Hear, O Israel: The Lord our God, the Lord is one!” (Deut. 6:4)
God is not only “one” numerically, He is also one of kind, or better, one without kind; He is the only God and He is not an individual member of a class of like beings, for there is no such class: He is unitas singularitatis. And not only is God one in number, admitting no kind or genus, He is also one in Simplicity; He is unitas simplicitatis. The latter sense of God’s one-ness is what theologians commonly refer to as the doctrine of Divine Simplicity. Stated briefly, the doctrine acknowledges the Biblical truth that God is not composed of parts.