Hadith
A body of traditions recording the sayings, deeds and tacit approvals attributed to the Prophet Muhammad, transmitted orally for generations before being systematically compiled in writing during the eighth and ninth centuries, and constituting, after the Quran, the second main source of doctrine, law and religious practice in Islam. Each hadith consists of two parts: the isnad, the chain of transmitters linking the text to the Prophet through successive generations of narrators, and the matn, the actual content of the tradition, whether a saying, an account of an action, or a significant silence in the face of someone else's conduct. Faced with the massive proliferation of traditions attributed to the Prophet —many of them fabricated for political, sectarian or pious motives during the early centuries of Islam— Muslim scholars developed their own critical discipline, the science of hadith (ulum al-hadith), aimed at assessing the reliability of each chain of transmission by examining the moral integrity, memory and generational continuity of the narrators, classifying hadiths according to their degree of certainty into categories such as sahih (authentic), hasan (good) or da'if (weak). From this critical effort emerged the great canonical compilations, especially those of Bukhari and Muslim in the ninth century, considered the most reliable by the Sunni majority, along with four other collections completing the 'six books' (Kutub al-Sitta). Shia tradition, for its part, developed its own compilations, granting special authority to hadiths transmitted through the imams of the Prophet's family. Hadiths perform an essential interpretive function by complementing and giving concrete shape to the often general precepts of the Quran, providing the detailed basis for much of Islamic law (fiqh), ritual practices and everyday Muslim ethics, while also being the object of constant theological and legal debate over their authenticity and their relative normative weight against the Quranic text.