One of the most important points about the holy Qur`an is its «revelation». The revelation of the Qur`an meaning that the words of the Qur`an, and also the meaning of them, were revealed to the Prophet (s) by the Lord. The authenticity of the revelation of the Qur`an is accepted by various Islamic sects. But a number of orientalists have scrutinized this fundamental Islamic belief with a negative and dubious attitude since long time ago. They believe that the verses of the Qur'an are a non-revelatory text which originated from the books of the previous religions, culture, customs and traditions of the "Jahiliyya" . «William Federer», the contemporary American author and historian, like many previous orientalists, has not accepted the authenticity and revelation of the Qur`an. The present study, by a descriptive-analytic method, discusses the various aspects of Federer`s claim. According to Federer, the similarity of the provisions of the verses of the holy Qur`an and the holy texts of other religions indicates the adaptation of the Qur`an from those texts. It is obvious that the similarity between two texts does not necessarily mean the adaptation of the latter text from prior text, especially if the latter text is excellent, and beyond of the incompetency of the prior text. The result of this research shows that, contrary to Federer`s claim, the adaptation of the Qur`an from any internal and external sources is unreasonable and dismissed. The result of this research has clear usage in the field of Qur`anic studies, orientalism, and also in theological and exegetical discussions. Multireligious
