The term hadeeth has become a synonym for the term sunnah, though there is
some difference in their meanings. Sunnah, according to Arabic lexicographers,
means ‘a way; course; rule; manner of acting or conduct of life’. Sunnah, as a
technical term in the Science of hadeeth, refers to whatever statements, acts,
approvals, physical or character descriptions that are attributable to the Prophet (Allaah exlat his mention and give him peace) along with his biography before or after the beginning of his prophethood. It is thus synonymous with the term hadeeth.
However, according to Usool al-Fiqh science (legal methodology), sunnah
refers to only the statements, acts and approvals of the Prophet (Allaah exlat his mention and give him peace). It also refers to whatever is supported by evidence from the sharee‘ah; the opposite of bid‘ah. And in the Legalistic science of Fiqh the term sunnah refers to recommended acts authentically attributable to the Prophet (Allaah exlat his mention and give him peace); the doer of which is rewarded and the non-doer is not punished. It is also used to refer to the opposite of bid‘ah as in the statement: Sunnah divorce and Bid‘ah divorce.
According to its general definition, the Qur’aan is the most important part of
the sunnah conveyed by the Prophet (Allaah exlat his mention and give him peace). It may also be said that the hadeeths were the containers in which the sunnah of the Prophet (Allaah exlat his mention and give him peace) was conveyed during his life time and after his death.
[Taken from Usool al-Hadeeth by Dr. Abu Ameenah Bilal Philips]
