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,
Criticism of Hadith to be obsessed with isr’iliyyat, i.e. tales from Jewish lore about earlier prophets. According to author Israr Ahmed Khan, traditional methods used to establish authenticity of hadith rely almost entirely on the personal characters of the reported narrators, and fail to pay enough attention to the actual content of the hadith being evaluated. Among the problems he sees in the traditional hadith analysis are: the inability of some narrators to maintain preciseness of the report, textual conflicts among reports, ignoring textual analysis when the hadith was reported by a narrator of good character, and probability of fabrication of hadith. Related