Before elaborating on these principles, we will first have a look at the grounds on the basis of which a Hadīth is accepted or rejected. It is the chain of narration of a narrative which makes it a Hadīth that can be attributed to the Prophet (sws). In addition to any hidden flaws in the chain of narration of a Hadīth, the trustworthiness of the narrators , their memory and the contemporaneous of the narrators are the three standards which should be kept in consideration in the light of the material which the scholars of Hadīth have painstakingly made available. This is the standard which scholars of Hadīth have put forth for the examination of the chain of narration of a Hadīth, 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-Jāmi al-Sahīh of Imām Bukhārī, al-Jāmi al-Sahīh of Imām Muslim and the Mu’attā of Imām Mālik can be accepted without application of this standard.