This is what God is for us. But we must admit that we have no right to call him Father, to be his children, to address him in this manner. He is our Father and we are his children by virtue of the natural relationship existing between him and Jesus Christ, by virtue of this Fatherhood and this Sonship which were made real in the person of Jesus Christ; and for us they are made real in him. We are his children and he is our Father, by virtue of this new birth realized at Christmas, on Good Friday, at Easter, and fulfilled at the moment of our baptism. It is a new birth, that is to say a new existence, really new, a life quite different from the one that can be born of our human possibilities, of our own merits. "God our Father" means "our Father of mercy." We are and always shall be prodigal sons who can claim no other right than that which is given us in the person of Jesus Christ.
This does not weaken what has been said of the divine Fatherhood. The clarity and the certitude, the very greatness and majesty of our Father appear in the fact that we find ourselves before him without power, without merit, without proper faith, and empty-handed. Yet in Christ we are the children of God. The reality of Sonship would not be more certain if there could be added to it anything whatsoever coming from us. The divine reality alone is the fullness of all reality.
Jesus Christ is the donor and the warrant of the divine Fatherhood and of our filiality. It is the reason for which this Fatherhood and this filiality are incomparably superior to any other, to any relationship suggested to us by the words "father," "son," and "children." These human bonds are not the original, of which the other would be the image or symbol. The original, the true fatherhood, the true filiality are in the ties which God has created between himself and us. Everything which exists among us is merely the image of this original filiality. When we call God our Father, we do not fall into symbolism; on the contrary, we are in the full reality of these two words: "father" and "son." (Barth: Prayer 24-25)