Barth’s theology is really just a reiteration of patristic and Athanasian theology, but in modern dress. Genuinely Christian theology is necessarily eschatological, because its subject is God’s Eschatos for the world, who is Jesus Christ. If the world was created so that Christ might be born, this entails that the world’s history was given its telos from its eschatological ground first actualized, even in the Logos incarnandus, in God’s choice to not be God without us in Jesus Christ. This is the pre-dogmatic basis by which a genuinely Christian prolegomena (theological methodology) ought to be grounded. That is, that there is no theology until Deus dixit (God has spoken); and He has spoken ever before we were. If we are ex nihilo, out of nothing, but God’s Word, then the Christian’s entire knowledge of God is based not on a generic or general categorical substratum of God’s being discovered in the effects of the world, but instead, our knowledge of Him is fully predicated on His coming into the world in the very Word of God that sustains said world. That is to say, there is no abstract knowledge of God in the world, simply because this world is not abstract; it is always already concrete in its orientation as it has orientation by the One who upholds it by the Word of His power.
To attempt to think godness from a posteriori basis that is not radically given by the miracle of the incarnation, is only to project an alien framework onto God that has been imagined by might, and by power, but not the Spirit. The human being, by nature, in its fallen state, always desires to have some say in who they believe God to be. When theological prolegomena are developed in such a way that this status becomes absolutized, as it has been in many iterations of so-called classical theism, then all the seeking Christian ends up with is a way to think God that is not principally based on God’s Self-revelation in Jesus Christ; but instead, one that is abstractly based on the whims and imaginations of the geniuses of some of the smartest people the world has ever encountered. But who God is for the world is not predicated upon the geniuses of the world’s smartest people, it is instead based upon God’s free choice to reveal Himself in a way that He would be mistaken as a common thief, or a false prophet; foolish and weak.