Hadith root of why there is no single "fiqh" system, but rather a collection of parallel systems within Islam. Much of early Islamic history available today is also based on the hadith, although it has been challenged for its lack of basis in primary source material and the internal contradictions of the secondary material available. Hadith may be "hadith qudsi" (sacred hadith) — which some Muslims regard as the words of God (Arabic: Allah) — or "hadith sharif" (noble hadith), which are Muhammad's own utterances. According to as-Sayyid ash-Sharif al-Jurjani, the hadith qudsi differ from the Quran in that the former
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: