The credibility of Christianity as a revealed religion, which comes first of all from the authority of God who reveals Himself, is one of the key topics of fundamental theology. A theologian's task is to analyse the Revelation which remains at the bottom of this religion. The author of this article analyses the problem of recognizing the Divine Revelation, present in the Bible and Tradition, according to two Polish theologians: E. Kopec and J. Myskow. In their works E. Kopec and J. Myskow describe difficulties in the correct understanding of the Revelation. They both remind of the personalistic character of the Revelation. They both also say that it is not possible to make a clear distinction between the Tradition and the Bible because it is God Himself who made them one - they are strictly connected to one another. E. Kopec in his scholar works very often says that the positive attitude of the Church to non-Christian religions and seeing in them the elements of truth and holiness - which is clear especially in the Declaration Nostra aetate of the Second Vatican Council - is the source of new ideas in theology, and that it specifically makes the establishment of the theology of religions possible.