Hadith (حديث ḥadīṯ; pl. aḥādīth, أحاديث, ʾaḥādīṯ, literally means “talk” or “discourse”) or Athar (أثر, ʾAṯar, literally means “tradition”) in Islam refers to what the majority of Muslims believe to be a record of the words, actions, and the silent approval of the Islamic prophet Muhammad.
The Quran is the most sacred text, as it is believed to be the literal word of God (Allah) as revealed to Muhammad. The Hadith is a secondary text that records sayings of Muhammad and his followers. These two texts form the basis for all Islamic theology, practice and Sharia (Islamic law).
Al-sīra al-Nabawiyya (Prophetic biography) is the traditional Muslim biographies of Muhammad from which, in addition to the Quran and trustable Hadiths, most historical information about his life and the early period of Islam is derived.