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 terminology in and of itself"with the same definition a "ṣaḥīḥ hadith" except that the competence of one of its narrators is less than complete; while a "hadith" that is "ḥasan ligharihi" ("ḥasan due to external factors") is determined to be "ḥasan" due to corroborating factors such as numerous chains of narration. He states that it is then comparable to a "ṣaḥīḥ hadith" in its religious authority. A "ḥasan hadith" may rise to the level of being "ṣaḥīḥ" if it is supported by numerous "isnād" (chains of narration); in this case that "hadith" would be "ḥasan lithatihi" (""ḥasan" in and of itself")