Sunnah and hadith

In the context of biographical records of Muhammad, sunnah often stands synonymous with hadith since most of the personality traits of Muhammad are known from descriptions of him, his sayings and his actions after becoming a prophet at the age of forty. Sunnah, which consists of what Muhammad believed, implied, or tacitly approved, was noted down by his companions in ahadith. Allegiance to the tribal sunnah had been partially replaced by submission to a new universal authority and the sense of brotherhood among Muslims.[5]
Early Sunni scholars often considered sunnah equivalent to the biography of Mohammed (sira) as the hadith which was then poorly validated while contemporary accounts of Muhammad's life were better known. As the hadith came to be better documented and the scholars who validated them gained prestige, the sunnah came often to be known mostly through the hadith, especially as variant or fictional biographies of Muhammad spread.[citation needed]
How far hadith contributes to sunnah is disputed and highly dependent on context.[citation needed] Classical Islam often equates the sunnah with the hadith. Scholars who studied the narrations according to their context (matn) as well as their transmission (isnad) in order to discriminate between them were influential in the development of early Muslim philosophy. In the context of sharia, Imam Malik and the Hanafi scholars are assumed to have differentiated between the two: for example Imam Malik is said to have rejected some traditions that reached him because, according to him, they were against the "established practice of the people of Medina".