Hadith that is reported by a trustworthy person on the authority of a trustworthy narrator. It is also the Hadith that is reported by trustworthy narrators who are of good memory on the authority of a Companion and that Companion has only one narrator to narrate his Hadiths.
For example: The Hadith of Urwah ibn Mudarris At-Ta'y who narrated: "I came to the Messenger of Allah (peace be upon him) while he was in Muzdalifah (a place outside Makkah). I said: O Messenger of Allah, I came to you from the two mountains of Tay'. I fatigued my horse and overtired my mount. By Allah, I never passed by a mountain but I stood on it; is my pilgrimage accepted?" This Hadith is one of the fundamentals of Shari ah and is accepted by all jurists. The narrators of the Hadith are all trustworthy but Al Bukhari and Muslim did not report it in their Sahih because there was no narrator from Urwah ibn Mudarris except Ash-Sha by.
The examples of such Hadiths are found numerously among Companions such as Qays ibn Abu Gharazah Al Ghifary despite his frequent narrations from the Messenger of Allah (peace be upon him) he did have but one narrator who was Abu Wa'il Shaqiq ibn Salamah.
Abu Wa'il was one of the grand Followers in Kufa who lived in the time of Umar, Uthman, Ali, and their successor Companions. Despite the fame of Usamah ibn Sharik and Qutbah ibn Malik among scholars, they had no narrator except Ziyad ibn Ilaqah who was one of the grand Followers.
There were many Companions whose Hadiths were treated the same and Al Bukhari and Muslim did not narrate them in their Sahih although their Hadiths were widespread among jurists and were held as proofs in the chains of transmission.
The third type of the agreed upon:
The news reported by a group of the Followers on the authority of Companions. The Followers were trustworthy men nevertheless each one of them had only one narrator to report his Hadiths such as: Muhammad ibn Hunayn, Abdur-Rahman ibn Farrukh, Abdur-Rahman in Ma bad and others who did not have but one narrator who was Amr ibn Dinar who was the Imam of Makkah. Likewise was Muhammad ibn Muslim Az-Zuhry who was the only narrator of a group of the Followers of whom were Amr ibn Aban and Muhammad ibn Urwah ibn Az-Zubayr.
Yahya ibn Sa id Al Ansary was the only narrator of a group of the Followers, and these narrations are not found in the Sahih of Al Bukhari and Muslim although they were all authentic through the narration of a trustworthy person from another, and they are widespread among jurists and have been used as proofs.
The fourth type of the agreed upon:
Single Hadiths that are reported by trustworthy narrators which have no ways of transmission written in books such as the Hadith of Al Ala' ibn Abdur-Rahman from his father on the authority of Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace be upon him) said: "When it comes the 15th of Sha ban, do not observe fast until Ramadan comes." Imam Muslim reported most Hadiths reported by Al Ala' in his Sahih but left this Hadith and the like which Al Ala' reported from his father on the authority of Abu Hurayrah.
Likewise the Hadith of Ayman in Nabil Al Makky from Abu Az-Zubayr on the authority of Jabir ibn Abdullah that the Messenger of Allah (peace be upon him) used to say in Tashahhud (a recitation in the sitting position in the second/ last unit of Prayer): "In the name of Allah and by Allah." Ayman ibn Nabil was a trustworthy narrator whose Hadiths were reported in Sahih Al Bukhari, but Imam Al Bukhari did not report this Hadith because he did not have another narrator from Abu Az-Zubayr who was trustworthy.
The examples of these Hadiths are numerous and they all were authentic but were not reported in Sahih Al Bukhari and Muslim; so we only mention few examples to denote the numerous examples that we did not mention.
The fifth type of the agreed upon:
Hadiths that were reported by a group of narrators from their fathers from their grandfathers, and narrations were not known in this sequence except from their way of transmission such as the Hadiths of Amr ibn Shu ayb from his father from his grandfather who was Abdullah ibn Amr ibn Al Aas.
Likewise Bahz ibn Hakim from his father from his grandfather who was Mu awiyah ibn Haydah Al Qushayry. Both Bahz and Mu awiyah were Companions and their grandchildren were trustworthy, and their Hadiths were numerous and have been held as proofs by scholars, but they were not mentioned in Sahih Al Bukhari and Sahih Muslim.
The sixth type is the first type of controversial Hadiths: Mursal Hadiths (the link between the Successor and the Prophet (peace be upon him) is missing) which have been mentioned earlier and the difference of scholars regarding accepting them, acting according to them, refusing them, and abandoning taking them as proofs in the fifth type from the first chapter.