Explanation and critique of Paul Tillich's theory of symbolic language

Paul Tillich (1965-1886) was a German Christian theologian who sees the symbolic language of religion. That is the realm of religion is full of religious symbols. Religious symbol is an icon who represents the last attachment. On Tillich''s view، all religious statements are symbolic statements، except that «the existence of God». He believes God is existence itself not a being among the others. In this article the author explains his theory and critique it. So he concludes that even there is some symbolic expressions in religious text، especially in the Holy Quran، but that does not mean totally the language of religion، is the symbolic language.