Ḥadīth

The term hadīth 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 ahadīth. The hadīth has come to supplement the Quran as a source of the Islamic religious law. The hadīth is the second pillar after the Quran upon which every Muslim rests his faith. But a fairly small number of fundamentalist Quranists reject the hadīth as authentic holy texts.

All Muslims, be they Sunni or Shia, agree that the hadīth are essential to understanding Islam. Ḥadīth are important because without them the Quran is hard to interpret. They provide a context to the verses in the Quran. The Quran is a rather concise book and therefore contains many general statements. For instance, the Quran commands Muslims to pray, but it does not provide the details of how one is to perform prayer. The Quran also commands Muslims to perform pilgrimage and give charity, but it does not provide the details. These details are found in the hadīth where they explained the details and mechanics of prayer. 

Unlike the Quran, the hadīth 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 hadīth collections were slow to evolve, some not taking full shape until the 8th and 9th centuries CE. Some hadīth include questionable and even contradictory statements, the authentication of hadīth became a major field of study in Islam. 

The Sunni and the Shia branches of Islam differ in their views on which hadīth are acceptable and authentic, due to disagreements on the reliability of the original transmitters. 

There are six canonical hadith collections that are widely accepted by Sunni Muslims. The two most famous are those of Muhammad ibn Isma‘il al-Bukhari (810–870) and Muslim ibn al-Hajjaj (817–875), both of which have the same title al-Sahih (The Authentic). Each hadith usually begins with the chain of the narrators (isnad) going back to the time of the Prophet Muhammad and his companions, which is then followed by the text of the tradition itself.

Below is a picture of a page of the oldest dated manuscript of al-Bukhari’s collection of hadith:

Further information of hadīth can be found in the paper titled Orientalists' Perspectives on Hadīth by Shaffat, et al.