IN ORDER TO appreciate the underpinnings of the Islamic sources (the Ḥadîth, in addition to the Quran), we must have some acquaintance with the Islamic Science of Ḥadîth (‘science’= organized observational and analytical technical apparatus for systematic study), which was developed in the early centuries of Islam in order to authenticate some—and reject others—of the hundreds of thousands of accumulated reports dealing with what Prophet Muhammad oe had been observed to say and do.
Elsewhere, we look at khabar al-âhâd (solitary reports) after first introducing the overall Science of Ḥadîth (Muṣṭalaḥ Al-Ḥadîth), and then explaining what constitutes the category of the mutawâtir (“widely transmitted”) report.
Under the heading of khabar al-â ḥâd, it is noted that reports of the “single [line of] transmission” (âḥâd), (= any reports not meeting the multiple line standard of the mutawâtir category) are categorized according to the number of people, at each level who have transmitted any given report:
Mashhûr (“well known”): reported by three or more people at every level of its ḥadîth chain
ʿAzîz (“rare” or “strong”): reported by no less than two people at every level of its hadîth chain
Gharîb (“strange” or “alien”): one or more levels of its ḥadîth chain having only one reporter
A (vertical) ‘chain’ of transmission links one (âḥâd )or more (mutawâtîr) transmitter(s) from among one generation of reporters to the next, starting from those who were eye-witnesses of the Prophet’s words or acts and ending with the final reporter/compiler of a ḥadîth, centuries later. The horizontal ‘width’ of reporting has to do with the plurality of people who heard the report from someone at the earlier level in the vertical chain and thus created other branches of [vertical] chains— of the same event using the same reported wording.
Horizontally-speaking, a widely-reported (=mutawatîr) event has greater weight than does a singularly-reported (=âhâd) one—since many within one generation of people have heard and in turn passed on the report in the first (mutawâtîr) case and only one reporter within the a generation has heard and reported the event in the second (âḥâd) case.
In general, the greater number of [reliable] transmitters that a report has associated with it, at each level, the higher is its rating of authenticity. The project of cataloging transmitters and evaluating their reliability was another—and extensive—early activity within the Islamic Science of Ḥadîth. From the standpoint of end result, any âhâd ḥadîth falls under one of two categories:
—whether the âḥâd hadîth in question be mashhûr, ʿazîz, or gharîb (whereas all mutawâtir reports are accepted).
There is consensus that any maqbûl ḥadîth, (accepted report) is part of divine revelation and is of a binding nature, meaning it must be followed and obeyed and can be used as proof for or against a jurisprudential ruling. Now, any maqbûl ḥadîth falls under either one or the other of two categories: Ṣaḥîḥ or ḥasan.
What Is A “Sahih Hadith”?
The word ‘ ṣaḥîḥ’ in the Arabic language means ‘sound.’ Hence, a “ḥadîth ṣaḥîḥ” is a “sound report,” meaning that Ḥadîth experts (Muḥaddithîn) have taken a critical look at both (A) the chain of reporters (sanad), and (B) the text, or subject matter, (matn), and adjudged that report to be structurally sound and of verified content.
(A) Chain Of Reporters (Sanad)
When the Ḥadîth experts (Muḥaddithîn) inspect the chain of reporters (vertically=from the eye-witness(es) of the Prophet down to the collector of ḥadîth), they examine it against three criteria:
The Chain Of Reporters Is Unbroken – This means that every reporter identifies the one from whom he received the report, such that there is no missing link. For example, imagine five people:  Omar,  Ahmad,  Osama,  Khalid, and  Muhammad.
Omar  said to Ahmad :
“There was heavy traffic on the main street Thursday afternoon.”
Then Ahmad  told this to Osama .
Then Osama  told it to Khalid .
Then Khalid  told the same to Muhammad .
With the above scenario in mind, suppose that Khalid  had said to Muhammad 
“Osama  told me  that Ahmad  had told him  that Omar  had said: “There was heavy traffic on the main street Thursday afternoon.”
Such a report would be considered to have an unbroken chain. It has no missing links. Links , , ,  and  are all represented. Every transmitter in the chain is accounted for and identified.
By contrast, suppose[A] that Khalid  had said to Muhammad ,
“Omar  said [such and such]”
or, [B] that Khalid  had said to Muhammad ,
“Ahmad  said that Omar  said [such and such]”
Each of the two above supposed cases exemplifies a report with a broken chain. In the first case, there were two missing reporting links, namely  and . In the second, there was one missing link, namely .
One can see that the links need not be presented in chronological order, , , ,  and —or even , , ,  and ; however, it is the case that the Arabic wording in the sanad does represent all parts of the chain that are actually present, even if some parts are in inverted order.
Every Person In The Chain Is Of Upright Character – The experts look for this to rule out the possibility of falsification. A believing person of upright character would not lie about what he had seen the Prophet say or do because he would know that bearing false witness on so important a matter could mean for him punishment in Hell-fire. Nor would a reputable transmitter falsify the chain of transmission of a report.
Every Human Link In The Chain Of Reporters Has A Demonstrably Good Memory And Linguistic Grasp Of Arabic – This is to rule out mistakes. Someone with a good memory, a good grasp of how the Arabic language works, and one who is attentive to detail in general is very unlikely to make a mistake in transmitting a report.
(Criteria Two and Three are established through broad and extensive critical and comparative examination of the record of their lives and reports about them from others.
(B) Text (Matn)
After testing the chain of reporters, Ḥadîth scholars take a critical look at the text of the report (matn), mainly judging by two criteria:
Absence Of Contradiction – The matn, or Text, of the report contains nothing that contradicts any other report transmitted by a person of stronger memory, better linguistic skills, and who is of more upright character.
Absence Of Report-Weakening Flaws – The Text of the report is free of problems that compromise it and render it weak. These problems are not categorized according to hard-and-fast problem types. Rather, any type of problem in general in the Text could render it weak. This criterion obviously depends upon prodigious knowledge of Revelation and Islam overall. Thus, it is only those who are very well versed in the science of Ḥadîth that are capable of accurately recognizing these problems.
So imagine that you were able to identify every transmitter of a certain report. And imagine that you came to know for certain that none of them were likely to lie or make any technical mistakes. And imagine that you saw that the content of the report held no contradictions or anything that would make you suspect its lack of soundness—if you are able to imagine such a scenario, you will be able to understand how a ṣaḥîḥ ḥadîth is properly verified and adjudged authentic.
The following is a translation of a common textbook-definition of a ṣaḥîḥ hadith:
Ṣaḥîḥ Ḥadîth: A person of upright character and sound memory with a good grasp of Arabic reports to one like him (in strength of memory, character, and language) and so on from the beginning of the chain to the end without any aberration (shuthûth) or defect (ʿillah) in the Text of the report.
And here is its accompanying example: The following chain of transmitters is recorded as belonging to a ṣaḥîḥ ḥadîth, as reported by Bukhâri. (Numbers indicating level-of-transmission have been added for clarity.)
* ʿAbdullah ibn Yûsuf  told us 
* that Mâlik  reported to us [5, 6]
* On the authority of Ibn Shihâb 
* On the authority of Muḥammad ibn Jubayr ibn Muṭʿam 
* On the authority of his father Jubayr ibn Muṭʿam , who  said:
* “I  heard the Messenger of Allah oe recite Sûrat Al->ûr during the Maghrib ṣalâh”
Such a ṣaḥîḥ ḥadîth chain of transmission has the following characteristics:
- All the reporters of this ḥadîth have been noted as having good memory, upright character ,and good grasp of Arabic).
- There are no missing links in the chain.
- There is nothing in the Text that contradicts reason or contradicts another Text (Quran or ḥadîth).
- There is nothing in the Text that seems problematic.
Accordingly, this ḥadîth is rated as ṣaḥîḥ. Once a ḥadîth has fulfilled all the conditions for a ṣaḥîḥ ḥadîth, it is incumbent, by consensus of the scholars, on every Muslim to accept it as a part of Revelation. Grasping the concept of a ṣaḥîḥ ḥadîth is at the core of understanding the science of ḥadîth (Muṣṭalaḥ Al-Ḥadîth) because everything else is a variation on this scenario.
More On Categories Of Hadith
An “accepted” ḥadîth (maqbûl ḥadîth) which is not Ṣaḥîḥ (“sound”) but rather belonging to the second category, ḥasan (“good”), is to be explained elsewhere, as are the various other categories of the “single transmitter reports” (âḥâd)—as well as ḥadîth having multiple transmission chains.
It is the “sound” Ṣaḥîḥ ḥadîth which are the most widely quoted since they are considered optimally authentic and trustworthy. Texts coming from the extensive ḥadîth collections of Bukhâri and Muslim were painstakingly investigated by those Muḥaddithîn before rating them Ṣaḥîḥ; there are other, lesser known collections of Ṣaḥîḥ ḥadîth, as well.