Is God Knowable? Paul addresses this fundamental question - not only for theology, but also for philosophy and the sciences as a whole - in Rom. 1.19 ff. He is familiar with the Old Testament and the Jewish tradition, but also knows the Greek popular philosophy of his time. What Paul explains about this has become fundamental for Christian preaching and instruction, teaching and theology. Paul teaches: God is knowable, namely as the Creator out of and in his creative activity, but he cannot be grasped in his essence. In the background of Rom 1.19 f. stands, factually interwoven with the idea of creation, the theologumenon of God's revelation through his works. It is of Old Testament origin, but was also used in Hellenistic-Jewish theology at the time of Paul. For Paul it is not part of a "natural theology", but rather of the biblical understanding of revelation. It is therefore a criterion for the proper evaluation of religion and religiosity. Of course, this can only be the case if the distinction between pagan religiosity and Judeo-Christian revelation is maintained. In the theology of the twentieth century, both in exegesis and dogmatics, this demarcation has been blurred beyond recognition. The aim of the present work is to help ensure that this revelatory theological criterion is reasserted in theology and the church when assessing what is to be understood by natural religion and theologia naturalis