It is the chain of narration of a narrative which makes it a Hadith that can be attributed to the Prophet (sws). In addition to any hidden flaws in the chain of narration of a Hadith (‘ilal), the probity of the narrators (‘adl), their grasp and memory (dabt) and their contemporaneousness (ittisal) are the three standards which should be kept in consideration in the light of the material which the scholars of Hadith have painstakingly made available. This is the standard which scholars of Hadith have put forth for the examination of the chain of narration of a Hadith, and is so sound that no addition can be made to it nor anything taken away from it.
Since attributing something suspect to the Prophet (sws) can be of severe consequences in this world and in that to come, it is necessary to apply this standard without any lenience and with absolute impartiality to every narrative attributed to him. Only those narratives should be considered acceptable which fully conform to this standard. Thus no narrative attributed to the Prophet (sws) even if found in primary works as the al-Jami al-sahih of Imam Bukhari, al-Jami al-sahih of Imam Muslim and the al-Mu’atta of Imam Malik can be accepted without application of this standard.
. The soundness of character of the Companions of the Prophet (sws), however is an exception and does not need the conformation of any standard. The Almighty Himself has borne witness to it in His Book. See: The Qur’an, 3:110.