A group of outsiders who had worn the dress of Islam and...

A group of outsiders who had worn the dress of Islam and also some of the enemies within ranks of Islam began to change and distort some of the hadith and thus diminished the reliability and validity of the hadith that was then heard and known. For this very reason Islamic scholars began to think of a solution. 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 Shi'ism in Authenticating the Hadith Shi'ism, in addition to seeking to authenticate the chain transmission of hadith,