But the self-humiliation of God in his Son is genuine and actual, and therefore there is no reservation in respect of his solidarity with us. He did become... the brother of man, threatened with man, harassed and assaulted with him, and with him in the stream which hurries downwards to the abyss, hastening with him to death, to the cessation of being and nothingness. With him he cries - knowing far better than any other how much reason there is to cry: "My God, my God, why hast thou forsaken me?" (Mk. 15:34). Deus pro nobis means simply that God has not abandoned the world and man in the unlimited need of his situation, but that he willed to bear this need as his own, that he took it upon himself, and that he cries with man in this need.
CD IV/1, p. 215