“…the doctrine of the Trinity itself is threatened by the same danger, the danger of irrelevant speculation, if we state it only at a later stage and do not give it the first word as that which gives us information on the concrete and decisive question: Who is God?

The common idea that one must follow the far too obvious and illuminating scheme: How do we know God? Does God exist? What is God? and only last of all: Who is our God? is in direct contradiction to the very important declarations that no one can then avoid making about the actual and comprehensive significance of the doctrine of the Trinity. What we are trying to bring to practical recognition by putting it first is something which has not been concealed in the history of dogmatics and which has often enough been stated very strongly, namely, that this is the point where the basic decision is made whether what is in every respect the very important term “God” is used in Church proclamation in a manner appropriate to the object which is also its norm. The doctrine of the Trinity is what basically distinguishes the Christian doctrine of God as Christian, and therefore what already distinguishes the Christian concept of revelation as Christian, in contrast to all other possible doctrines of God or concepts of revelation. Certainly, the decision is repeated at every stage. But it is from this point that it is repeated. This is where it gains its momentum.

Church Dogmatics, Vol.1.1, 1932. p.301

John 1:18 No man hath seen God at any time, the only begotten Son, which is in the bosom of the Father, he hath declared him.

Barth regarded natural theology as demonic. In the Preface to the above cited book, he declared that the analogia entis embraced by Roman Catholicism was the invention of the Antichrist. A theology that begins with nature and then proceeds to the question of divine existence and so on to Christian doctrine is ruined from start. He referred to this process as grace being converted into nature, a thesis that would later be developed further by Francis Schaeffer in his Escape from Reason (1968). He writes:

“… grace here becomes nature, the action of God immediately disappears and is taken up into the action of the recipient of grace, that which is beyond all human possibilities changes at once into that which is enclosed within the reality of the Church, and the personal act of divine address becomes a constantly available relationship.” (pp.40,41)

“[Roman Catholic faith] affirms an analogia entis, the presence of a divine likeness of the creature even in the fallen world, and consequently the possibility of applying the secular “There is” to God and the things of God as the presupposition, again ontological, of that change or transformation, of that depriving of revelation and faith of their character as decision by evasion and neutralisation. (p.41)