The article elucidates the significance of words of Itrat (the family of the Prophet-saw) in interpretation of the Qur'an and touches upon the authority of Hadith-i- Thaqalayn, quoting some points from several great scholars .while examining its contents. Then it proceeds to the expance of exegetical heritage of the infallibles and its status and role in Tafsir. Next, it examines the authority and validity of the non-conclusive narrations which have found their way into tafsir, brings up viewpoints of several well-known early and contemporary interpreters on validity of exegetical narrations, and tries to evaluate these viewpoints.