The term hadith (pronounced ha-DEETH) refers to any of the various collected accountings of the words, actions, and habits of the Prophet Mohammad during his lifetime. In the Arabic language, the term means "report," "account" or "narrative;" the plural is ahadith. Along with the Quran, the hadiths constitute the major holy texts for most members of the Islamic faith. A fairly small number of fundamentalist Quranists reject the ahadith as authentic holy texts.

Organization

Unlike the Quran, the Hadith does not comprise a single document but instead refers to various collections of texts. And also unlike the Quran, which was composed relatively quickly following the death of the Prophet, the various hadith collections were slow to evolve, some not taking full shape until the 8th and 9th centuries CE.

During the first few decades after the Prophet Muhammad's death, those who directly knew him (known as the Companions) shared and collected quotations and stories related to the Prophet's life. Within the first two centuries after the Prophet's death, scholars conducted a thorough review of the stories, tracing the origins of each quotation along with the chain of narrators through whom the quotation was passed. Those which were not verifiable were deemed weak or even fabricated, while others were deemed authentic (sahih) and collected into volumes. The most authentic collections of hadith (according to Sunni Muslims) include Sahih Bukhari, Sahih Muslim, and Sunan Abu Dawud.​

Each hadith, therefore, consists of two parts: the text of the story, along with the chain of narrators which support the authenticity of the report.

Significance

An accepted hadith is considered by most Muslims to be an important source of Islamic guidance, and they are often referred to in matters of Islamic law or history. They are regarded as important tools for understanding the Quaran, and in fact, provide much guidance to Muslims on issues not detailed in the Quran at all. For example, there is no mention at all of the details of how to correctly practice salat—the five scheduled daily prayers observed by Muslims—in the Quran. This important element of Muslim life is entirely established by hadith.

The Sunni and the Shia branches of Islam differ in their views on which ahadith are acceptable and authentic, due to disagreements on the reliability of the original transmitters. Shia Muslims reject the Hadith collections of the Sunnis and instead have their own hadith literature. The best-known hadith collections for Shia Muslims are called The Four Books, which were compiled by three authors who are known as the Three Muhammads.