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,
Introduction to the Science of Hadith the earlier scholars as appropriate and mostly sufficed with conclusions drawn from them and then specifying or clarifying a definition. The definitions Ibn al-Ṣalāḥ used to describe the individual terms of hadith terminology were largely in accordance with the views of the majority of hadith specialists. In some instances, he would mention an undisputed opinion, before mentioning one that was widely accepted and then describing the difference. He would generally precede his critique of differing opinions by saying: "I say". For the primary terms described, he mentioned an example to illustrate that definition. His goal in doing so was to