Again in Church Dogmatics The Doctrine of the Word of God, Volume 1, Part 2: The Revelation of God; Holy Scripture: The Proclamation of the Church, Barth teases out the “negative” consequences of the confession that God has revealed himself in Jesus. If, Barth argues, Jesus tells us that “God is free for us here,” in the incarnate Son, then it also means that “He is not free for us elsewhere. It limits the freedom of God for us to itself.”
And this, in turn, means that elsewhere God is “a God hidden from men” and apart from Christ men are “blind to God.” This is a hiddenness of God deeper and more radical than anything a skeptic or unbeliever imagines: “The God whose existence or manifestness they doubt or deny is not God at all. And so too His absence, as they think they should assert it, is not God’s absence at all.” God’s hiddenness and absence are known only by revelation: His hiddenness elsewhere than in Jesus, His absence anywhere but in the Name: “All general intellectual difficulties and impossibilities respecting knowledge of so-called supernatural things assert nothing at all in face of the negation of all other knowability of God which is achieved by God’s revelation itself” (28-29).
This holds even if we do not follow Barth in denying general revelation or in hedging on the Bible as revelation. Even we don’t follow Barth on these points, it is still the case that God is hidden outside of Jesus, and that God’s hiddenness is implied in the very specificity of His revelation.