Hadith remembers God unceasingly. (Al-Ahzab 33: 21) The hadith literature is based on spoken reports in circulation after the death of Muhammad. Unlike the Qur'an, ahadith were not promptly written down during Muhammad's life or immediately after his death. Hadith were evaluated and gathered into large collections during the 8th and 9th centuries, generations after the death of Muhammad, after the end of the era of the "rightful" Rashidun Caliphate, over from where Muhammad lived. "Many thousands of times" more numerous than Quranic verse, ahadith have been described as resembling layers surrounding the “core” of the Islamic belief (the Quran). Well-known,
Hadith of the Twelve Successors be from the tribe of Quraysh. Interpretation of the hadith varies widely among Sunni scholars; some have openly claimed that they do not know the meaning. Another interpretation is that the prophecy was fulfilled by the Rashidun Caliphs. Some commentators, such as Ibn Kathir and Ibn Taymiyya, link this hadith with the biblical account of Moses and his twelve deputies. Imam Muslim on Sahih Muslim wrote: Rasulullah s.a.w said: "This religion (Islam) will remain standing until twelve caliph, which all of them is from Quraysh, rule over you." (Sahih Muslim) Imam Abu Dawud on Shahih Abi Dawud wrote: Masyruq said: