In this study, first the reality of Ijtehad from the perspective of etymologists and scholars of legal theories from the two sects (Shia and Sunni) have been studied. We have chosen the best definition from amongst many definitions. Thereupon, the difference between Ijtehad in its present sense and Itjehad in the sense of juristic opinion (ra’y) has been explained, and it has been mentioned that when we talk of Ijtehad of the Prophet (pbuh), we mean the second Ijtehad not the first one.
For this reason, the opinion of those who believe in the necessity of the Prophet’s Ijtehad in the sense of juristic opinion has been put forth, assessed and criticized. The said opinion held and advocated by Sunni scholars has been proved to be baseless and unwarranted. They believe in the necessity of the Prophet’s Ijtehad considering it as esoteric revelation. While examining the validity of the said view, we have first explained the foundations of human sciences and the difference between the nature of revelation and Ijtehad and also that of Ijtehad and the Prophet’s legislations. We have mentioned the negative consequences of believing in the Prophet’s Ijtehad and have criticized the arguments presented by its advocates and also made known the contradictions in this regard. Finally, we have proved by presenting strong and indisputable arguments that Ijtehad in the said meaning is never permissible with regards to the Last of All Prophet (pbuh) because he is connected to the Unseen World and that his words and sayings are next to the Quran and their authoritativeness originates in the sources of revelation.
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