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 "with something, such as numerous chains of narration, strengthening it." Ibn Hajar's definitions indicate that there are five conditions to be met for a particular "hadith" to be considered "ṣaḥīḥ": A number of books were authored in which the author stipulated the inclusion of "ṣaḥīḥ hadith" alone. According to Ahl al-Sunna, this was only achieved by the first two books in the following list: "Ḥasan" ( meaning "good") is used to describe "hadith" whose authenticity is not as well-established as that of "ṣaḥīḥ hadith", but sufficient for use as supporting evidence. Ibn Hajar defines a "hadith" that is "ḥasan lithatihi"""ḥasan"