Given this situation, scholars realized the need to gather the Aḥādīth, or narrations of the Messenger ﷺ, to attain a correct and comprehensive understanding of his Sunnah.
Thus, the greatest Muslims from among them took the task of journeying through Islamic lands and gathering the transmitted narrations of his Sunnah. This time period is known as the era of collection (tadwīn).
This process began around ninety years following the passing of the Messenger ﷺ, and continued for approximately three centuries. During this time, the great collections of ḥadīth such as the Sunan of Abī Dāwūd, the Sunan of Ibn Mājah, and the Jāmi‘ of al-Tirmidhī, were compiled.
Moreover, in the era following the passing of the major companions, the Muslims were faced with challenges. Some of these challenges included the emergence of various sects and the rise of corrupt governments. Another challenge that they experienced was the presence of hypocrites who desired to sabotage the religion.
Taking advantage of the absence of a collection of āḥād Sunnah (aḥādīth containing non essential aspects of belief), certain narrators initiated forging narrations, either to benefit themselves, their sect, or to damage the faith and attributed them to the Messenger ﷺ. Some of these narrators later admitted to inventing such narrations.
One such example is that of ‘Umar bin Ṣaḥab. Al-Imām al-Bukhārī narrates in his book, Tārīkh al-Awsat, “Yaḥya bin Yashkury informed me from ‘Ali bin Jarīr who said, ‘I heard ‘Umar bin Ṣaḥab say, ‘I forged the khutbah of the Messenger ﷺ.’
A similar example that illustrates the invention of narrations by different sects for their own gain is found in narrations from Ibn Abi Ḥātim. He mentions a narration from a former scholar of the Khawārij after he left their sect, who said, “Be wary of whom you take your religion from, for indeed if we used to desire a matter, we would make it into a ḥadīth.”
This made scholars realize the necessity of distinguishing a true statement of the Messenger ﷺ from a forgery. Thus, a way of classifying ḥadīth was deduced.
In order to verify narrations, scholars developed a standard of accuracy in narration and trustworthiness to judge narrators on before accepting their reports.
Then, they would seek out the source that the narrator took the report from and apply the same standard of accuracy and trustworthiness to the previous narrator. That is how they traced the statement back to the Messenger ﷺ—verifying each narrator in the chain of transmitters.
The scholars understood the weight of classifying statements of the Messenger ﷺ, which constituted a large portion of the religion. Hence, they applied strict conditions when accepting narrations. Even if there was a single narrator within a chain of transmission who failed to meet the criteria of the scholars, the scholars would still classify the narration as weak due to a higher margin of error. Only those narrations that were transmitted through an entire chain of accurate and trustworthy narrators were classified as authentic.
Despite the high caliber of the accepted narrators, they were still fallible. Their narrations still entailed a possibility, albeit low, of error. Therefore, the scholars of ḥadīth took further nuanced measures to ensure that the narrations were free from mistakes.
In order to further verify the authenticity of a narration, all the chains transmitting it were compared. Additionally, the chains of the respective versions of that same narration were also compared.
Through this comparison, scholars were able to further filter reports by identifying mistakes and incorrect transmissions. An example of this is the ḥadīth of the Messenger ﷺ teaching the tashahhud
While quoting the ḥadīth, Abu Khaythama narrates the ending of the ḥadīth as such, “ ‘[…] I bear witness that there is no God but Allāh, and I bear witness that Muhammad ﷺ is His messenger.’ So when you have stated this, your salah is completed. If you wish to stand, you may.” An examination of all the chains through different narrators who transmitted this ḥadīth reveals that the portion of the following ḥadīth: “So when you have stated this, your salah is complete. If you wish to stand, you may,” is not from the Prophet.
That statement is actually the commentary of ‘Abd Allāh bin Mas‘ūd on the ḥadīth. In fact, a further examination of the transmission by other narrators through ‘Alqamah reveals that the mistake was only transmitted by Abū Khaythama, who mistakenly assumed that the entire statement was from the Messenger ﷺ and narrated it as such.
Through these methods of verifying the narrators, as well as comprehensive comparative analysis, true statements of the Messenger ﷺ were separated from those that were forged, incorrect, or entailed a high possibility of error.
Thus, although the Sunnah of the Messenger is binding, there is something to be said about its verification. While that which is authentic is binding, that which falls short of meeting the standard of authentication is not.