Hadith (/ˈhædɪθ/ or /hɑːˈdiːθ/; Arabic: حديث ḥadīṯ, plural: أحاديث, ʼaḥādīṯ) are collections of the reports claiming to quote what the prophet Muhammad said verbatim on any matter. The term comes from the Arabic meaning "report", "account" or "narrative". Hadith are second only to the Quran in developing Islamic jurisprudence, and regarded as important tools for understanding the Quran and commentaries (tafsir) on it. Many important elements of traditional Islam such as the five salat prayers, are mentioned in hadith but not the Quran. Different hadith are regarded with different levels of importance by different Muslims, although all variants emphasize the Sunnah.
The hadith literature is based on spoken reports that were in circulation in society after the death of Muhammad. Unlike the Quran itself, which was compiled under the official direction of the early Islamic State in Medina, the hadith reports were not compiled by a central authority. Hadith were evaluated and gathered into large collections during the 8th and 9th centuries, generations after the death of Muhammad, after the end of the era of the "rightful" Rashidun Caliphate, over 1000 km from where Muhammad lived.
Each hadith is based on two parts, a chain of narrators reporting the hadith (isnad), and the text itself (matn). Individual hadith are classified by Muslim clerics and jurists as sahih ("authentic"), hasan ("good") or da'if ("weak"). However, there is no overall agreement: different groups and different individual scholars may classify a hadith differently.
Different branches of Islam (Sunni, Shia, Ibadi, Ahmadiyya) refer to different collections of hadith, and the small heterodox Quranists reject the authority of the hadith collections.