The form of the Biblical authority is derived from the fact that the Bible is composed under the dictation of the Holy Spirit. This term, “dictation of the Holy Spirit,” is something which produced the doctrine of verbal inspiration, in a way which surpasses anything which existed in Calvinism, and in contradicting the Protestant principle as such: t he disciples were “pens” of Christ; all elements which come from them were superseded by the Divine Spirit which testifies that in this book the oracles of God are contained. “Between the apostles and their successors, however, there is this difference – that the apostles were the certain and authentic amanuenses of the Holy Spirit, and therefore their writings are to be received as the oracles of God.” Out of the mouth of God” the Bible is written, I. e., the whole Bible; the distinction between the Old and New Testaments largely disappears. And you can find this still today in every Calvinistic country.
Paul Tillich, A History Of Christian Thought – Table of Contents