Ḥadīth (ˈhædɪθ or hɑːˈdiːθ; حديث, , ħadiːθ, () , أحاديث, , ʔaħaːdiːθ, literally "talk" or "discourse") or Athar (أثر, , literally "remnant"/"effect") refers to what most Muslims and the mainstream schools of Islamic thought believe to be a record of the words, actions, and the silent approval of the Islamic prophet Muhammad as transmitted through chains of narrators. In other words, the ḥadīth are transmitted reports attributed to what Muhammad said and did.
Hadith have been called by some as "the backbone" of Islamic civilization, and for many the authority of hadith is a source for religious and moral guidance known as Sunnah, which ranks second only to that of the Quran (which Muslims hold to be the word of God revealed to Muhammad). Most Muslims believe that scriptural authority for hadith comes from the Quran, which enjoins Muslims to emulate Muhammad and obey his judgements (in verses such as , ).
While the number of verses pertaining to law in the Quran is relatively few, hadith are considered by many to give direction on everything from details of religious obligations (such as or , ablutions for prayer), to the correct forms of salutations and the importance of benevolence to slaves. Thus for many, the "great bulk" of the rules of Sharia (Islamic law) are derived from hadith, rather than the Quran.
is the Arabic word for things like speech, report, account, narrative. Unlike the Quran, not all Muslims believe that hadith accounts (or at least not all hadith accounts) are divine revelation. Different collections of hadīth would come to differentiate the different branches of the Islamic faith. Some Muslims believe that Islamic guidance should be based on the Quran only, thus rejecting the authority of hadith; some further claim that most hadiths are fabrications (pseudepigrapha) created in the 8th and 9th centuries AD, and which are falsely attributed to Muhammad. Historically, Mu'tazilites also rejected the hadiths as the basis for Islamic law, while at the same time accepting the Sunnah and ijma.