Hadith (ahadith in the plural) means “account, “report,” or “narrative,” and consists of mostly oral traditions of the life of the Prophet Muhammad and of early Islam that were passed down for more than 100 years after Muhammad’s death in 632 AD.
The ahadith, mostly consisting of oral traditions in circulation, were not penned during or even shortly after Muhammad’s life and death, and include numerous words and actions attributed to Muhammad that are not found in the Quran, the divinely inspired holy book of Islam. An example of this is the salat/salah, one of the five pillars of Islam that Muslims are obligated to follow. The ahadith are also considered important sources for not only understanding the Qur’an but also for religious law and moral guidance. Most of Islamic law (sharia) is derived from the ahadith as opposed to the Qur’an. It was only in the 8th and 9th centuries when Muhammad’s followers begun collecting and compiling ahadith into a corpus of literature.
Muslims who believe in the Hadith, which is the majority of those practicing their religion, are known as hadithists. The majority of Muslims believe that the ahadith are important but secondary to the Qur’an while a minority, known as the Quranists, reject the authority of the hadith collections altogether. Islamic scholars, noting problems within the ahadith traditions, have categorized them into four groups, namely, the sahih (“authentic”), hasan (“good”), da’if (“weak”), or Mawdu’ (fabricated).
Sahih, or authentic, hadith must have continuity in the chain of transmission, be free from contradiction with other established ahadith, and must have been conveyed by credible person who had memorized and preserved what he wrote. A credible narrator is one who is trustworthy in his religion, understands what he narrates, and can report the wording of the hadith verbatim. Taken to be the most trustworthy hadith is sahih al-Bukhari while others include sahih Muslim, sahih ibn Khuzaymah, sahih ibn Hibban, and Al-Mustadrak alaa al-Sahihain. Ḥasan, or good, ahadith are considered less credible than sahih ahadith although they can stand in as support evidence for sahih ahadith. The narrator of a hasan hadith is considered truthful and reliable, but is also considered less reliable in respect to his memory of hadith, especially when he is compared to the narrators of the sahih ahadith. To be a hasan, a hadith must also be free of irregularities. Da’if (weak) ahadith fails to obtain the status of hasan. They are considered weak because of doubt pertaining to their narrators and discontinuity in the chain of transmission. Such doubt concerning a narrator may be in respect him being judged as deceitful, prone to making mistakes, and in opposition to the narration of more reliable sources. Mawdu’ ahadith are considered fabrications and/or forgeries. These traditions contradict details in more reliable ahadith and its narrators are known to be liars. Some of these include Kitab al-Abatil by al-Jauraqany and Al-Mawduʻat by Ali al-Qari. These fabrications could be, although note limited to, the result of a heretic or because of some unknown personal reasons.