[2] Ibn Hajar defines a hadith that is ṣaḥīḥ lidhātihi ("ṣaḥīḥ in and of itself") as a singular narration (ahaad; see below) conveyed by a trustworthy, completely competent person, either in his ability to memorize or to preserve what he wrote, with a muttaṣil ("connected") isnād[broken anchor] ("chain of narration") that contains neither a serious concealed flaw (ʻillah, Arabic:علة) nor irregularity (shādhdh).
"[3][full citation needed] In the Sunni branch of Islam, the canonical hadith collections are the six books (Kutub al-Sittah) listed below.
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.
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") but, once coupled with other supporting chains, becomes ṣaḥīḥ ligharihi ("ṣaḥīḥ due to external factors").