quality:corruption, structural:reformatting
Shia and Sunni textual traditions

Sunni and Shia hadith collections differ because scholars from the two traditions differ as to the reliability of the narrators and transmitters. Narrators who sided with Abu Bakr and Umar rather than Ali, in the disputes over leadership that followed the death of Muhammad, are considered unreliable by the Shia; narrations attributed to Ali and the family of Muhammad, and to their supporters, are preferred. Sunni scholars put trust in narrators such as Aisha, whom Shia reject. Differences in hadith collections have contributed to differences in worship practices and shari'a law and have hardened the dividing line between the two traditions.