They created the sciences concerned with the biography of...

They created the sciences concerned with the biography of learned men and chains of transmission of hadith in order to be able to discriminate between true and false hadith. The Method of Authenticating the Hadith Shi’ism, in addition to seeking to authenticate the chain of transmission of hadith, considers the correlation of the text of the hadith with the Quran as a necessary condition for its validity.

In other words, conformity of contents of the hadith with the Qur’an is a way of establishing the authenticity of the hadith. In Shi’ite sources, there are many hadiths of the Prophet and the infallible Imams with authentic chains of transmission which themselves assert that a hadith contrary to the Quran has no value. Only that hadith can be considered valid which is in agreement with the Quran.

Based on these hadiths, Shi’ism does not act upon those hadiths which are contrary to the text of the Quran. As for the hadiths whose agreement or disagreement cannot be established, according to instructions received from Imams, they are passed by in silence without being accepted or rejected. Needless to say, there are also within Shi’ism those who, like a group among the Sunnis, act on any hadith whatsoever which they happen to find in different traditional sources.

The Method of Following the Hadith A hadith heard directly from the mouth of the Prophet or one of the Imams is accepted as is the Quran. As for hadiths received through intermediaries, the majority of Shi’ites act upon them if their chain of transmission is established at every step or if there exists definite proof concerning their truth, and, if they are concerned with fundamentals of religion which require knowledge and certainty, according to the text of the Quran.

Other than these two kinds of hadith, no other hadith has any validity concerning the fundamentals of religion, the invalid hadith being called “tradition with a single transmitter” (Khabar Wahid). However, in establishing the injunctions of the Shari’ah, because of reasons that have been given, Shi’ites act also on a tradition which is generally accepted as reliable.

Therefore it can be said that in Shi’ism, a certain and definitely established hadith is absolutely binding and must be followed, while a hadith which is not absolutely established but which is generally considered reliable is utilized only in the elaboration of the injunctions of the Shari’ah.