Pause for a moment, and ask yourself: what are the greatest accomplishments of the Muslim civilization? At first thought, a number of things will probably come to mind, ranging from mathematics to medicine to architecture—perhaps even coffee. But unfortunately we tend to overlook one of the greatest accomplishments, if not the greatest: the isnād system. That a person, till this day, can attribute a hadīth to the Prophet and then follow it with a list of authorities reaching back successively to the source is what scholars as early as Abū Bakr al-Thaqafī (d. 309 AH) described as an exclusive accomplishment of the Muslim civilization.
The word sanad (lit. base) refers to the chain of transmitters leading to the text of a hadīth while isnād refers to the mentioning of the chain. Majority of scholars, however, use both terms interchangeably.Al-Bukhārī (d. 256 AH), for instance, mentions, “Makkī ibn Ibrahīm—Yazīd ibn Abī ‘Ubayd Allāh—Salamah: I heard the Prophet (peace and blessings be upon him) say, ‘Whoever lies about me should prepare his abode in the fire.’” In this example, the names leading to the text form the sanad of the hadith.
The usage of isnād began simultaneously with the transmission of the Prophet’s hadiths. Companions like Abū Salamah al-Makhzūmī (d. 3 AH), and Ja‘far ibn Abī Tālib (d. 8 AH), who passed away during the Prophet’s lifetime, transmitted hadiths citing the Prophet as their source. Furthermore, Companions who were preoccupied with their daily responsibilities would take turns to attend the gathering of the Prophet. When the present partner would relate the day’s teachings to the absent partner, he would obviously preface his words with “The Prophet said so and so.” The shortness of the chain, i.e. direct transmission from the Prophet, makes this first rudimentary usage of isnād unnoticeable. During this time, transmitters were not required to disclose their sources. That is why we find Companions like Anas ibn Mālik, who lived during the Medinan period, relate incidents from the Meccan period without citing their sources. This was not an issue because even the thought of lying about the Prophet was inconceivable to the Companions.
Shortly after the Prophet’s demise, the Companions exercised caution vis-à-vis hadiths, with Abū Bakr spearheading the initiative. When al-Mughīrah ibn Shu‘bah narrated a hadith about a grandmother’s share of inheritance, Abū Bakr asked for corroboration, which Muhammad ibn Maslamah duly provided. ‘Umar ibn al-Khattāb also asked Abū Mūsā al-Ash‘arī for corroboration when he narrated the hadith about seeking permission thrice for entering a person’s house; in this case, Abū Sa‘īd al-Khudrī stood in his support.
The assassination of ‘Uthmān ibn ‘Affān (Allāh be pleased with him) in 35 AH, later described as the strife (Fitnah), marks a major shift in the course of Islamic history. Until the events that led to the tragic incident, there was considerable stability throughout the Muslim world. Driven by a thirst to bolster their political and theological views, people thereafter began to fabricate hadiths, which prompted scholars to exercise even further caution. Recounting this delicate phase, Ibn Sīrīn (d. 110 AH) explains, “In the early period, no one would ask about isnād. But when the strife occurred people would say, “Name for us your sources.” It is understood from Ibn Sīrīn’s words that the practice of citing one’s source, or isnād, for a hadīth existed before the Fitnah, but was not a requirement—it was within the discretion of a transmitter.
During the first century AH, the isnād system had fully developed and formed part and parcel of the transmission of hadiths. Until a hadith was supported by an isnād, it held no weight in the sight of Hadīth scholars. In this respect, ‘Abd Allah ibn al-Mubārak (d. 181 AH) made the proverbial remark, “Isnād is part of religion. Were it not for isnād, a person could say whatever he wanted. If you ask him, ‘Who told you this?’ He cannot reply.” Sufyān al-Thawrī (d. 161 AH) said, “Isnād is the weapon of a believer. When he is not equipped with his weapon, how will he combat?” The emphasis scholars placed on isnād in the field of Hadīth had rippling effects on other disciplines, like Qur’ānic exegesis, jurisprudence, history, and poetry. The leading exegete, Ibn Jarīr al-Tabarī (d. 310 AH), for instance, when quoting an opinion on the commentary of a verse, couples it with a chain of transmission that traces back to the source. The extent this emphasis permeated even the most mundane subjects is at times unbelievable. A collection of stories about love entitled “Masāri‘ al-‘Ushshāq” where the author, Abū Muhammad al-Sarrāj (d. 500 AH), painstakingly cites lengthy chains of transmission is a case in point.
An argument has been put forward for the usage of isnād before the advent of Islām, in an attempt to negate the notion that it is an exclusively Islāmic accomplishment. To this end, examples are adduced from pre-Islāmic poetry, Jewish scripture and Hindu literature. These examples, however, are not substantive; there is a stark contrast between the isnāds employed in these examples and how Muslims used isnāds. The fifth century Andalusian polymath, Ibn Hazm (d. 458 AH), explains what is meant by the exclusivity of isnād among Muslims. From six forms of transmission, he writes, three are exclusive to Muslims. The third form deserves particular attention, “Transmission from the Prophet via reliable narrators, each disclosing the name and lineage of the informant, and each of known status, person, time, and place.”
More simply put, Muslims may not have been the first to use isnād per se—for argument’s sake—but they were definitely the first to give it value by providing unbroken chains and documenting detailed accounts of the narrators, better known as the field of al-Jarh wa al-Ta‘dīl (accreditation and criticism). After all, what use is a list of narrators when nothing is known about them save their names? The Muslim civilization is truly unrivalled in its documentation of the biographical information of Hadīth transmitters. Aloys Sprenger (d. 1893 CE), the celebrated Western academic and critic of Islam, could not help but acknowledge this unparalleled accomplishment. He writes:
The glory of the literature of the Mohammedans is its literary biography. There is no nation, nor has there been any which like them has during twelve centuries recorded the life of every man of letters. If the biographical records of the Musalmans were collected, we should probably have accounts of the lives of half a million of distinguished persons, and it would be found that there is not a decennium of their history, nor a place of importance which has not its representatives.
Before concluding, it will be beneficial to address two issues. First, as the science of Hadīth developed, a hadīth was identified with its isnād and not its text (matn).  The growth of isnāds was a natural outcome of transmission: assuming one Companion imparted a hadith to five students who in turn did the same, etcetera, the number of routes would have increased exponentially. Through the process of transmission, therefore, the number of isnāds multiplied without an increase in the number of texts.Consequently, when ‘Abd al-Rahmān ibn Mahdī said, “I know thirteen hadīths via al-Mughīrah ibn Shu‘bah from the Prophet regarding wiping on the socks,” he was referring to a single text transmitted through thirteen different channels. Keeping this technicality in mind will allow us to understand what scholars meant when they described the staggering number of hadīths they knew, such as al-Bukhārī’s memorization of one-hundred thousand authentic hadiths or Ahmad ibn Hanbal’s compilation of his Musnad from a pool of seven-hundred thousand hadīths. Furthermore, apart from Prophetic hadiths, included in these large numbers are the statements of the Companions and Successors.
Second, simply citing a chain of transmission for a report, be it a hadith or otherwise, does not necessitate its authenticity. This is more so in the case of books like Ibn Jarīr al-Tabarī’s Tārīkh al-Umam wa al-Mulūk—a primary source for subsequent historians—where the author gathers all available reports as transmitted to him and then consigns the responsibility of analyzing the chains of transmission to the reader. But at the same time, it should be remembered that the isnād system, as Anwar Shāh al-Kashmīrī (d. 1933 CE) would often remind his students, was formally instituted to prevent the inclusion of extra-Islamic material, not to remove established Islamic teachings.
 See: 1001 Inventions: Muslim Heritage in Our World, pp.12, 64, 198.
 Al-Baghdādī, Sharaf Ashāb al-Hadīth, p.40. On the identity of Abū Bakr al-Thaqafī, see: Abū Ghuddah, al-Isnād min al-Dīn, p.23. Al-Thaqafī relates the idea of exclusivity from an earlier unidentified source. Muhammad ibn Hātim ibn al-Mufażaffar and Abū Tālib al-Makkī (d. 386 AH) have made similar remarks [al-Baghdādī, Sharaf Ashāb al-Hadīth, p.40; al-Makkī, Qūt al-Qulūb, vol.1, p.385]. I have yet to locate Muhammad ibn Hātim’s exact date of demise. Thus far, the following is some available data: (1) he reportedly narrates from Yahyā ibn Ma‘īn (d. 233 AH) [al-Bayhaqī, Shu‘ab al-mān, vol.4, p.362]; (2) Abū al-‘Abbās al-Daghūlī (d. 325 AH) [Al-Baghdādī, Sharaf Ashāb al-Hadīth, p.40] and Halīm ibn Dāwūd al-Kashshī (d. 357 AH) [Ibn Mākūlā, al-Ikmāl, vol.2, p.492] narrate from him.
 Ibn Hibbān, al-Majrūhīn, vol.1 p.30; al-Hākim, al-Mustadrak ‘alā al-Sahīhayn, vol.1, p.41; al-Kattānī, Fahras al-Fahāris, vol.1, p.80.
 Ibn Jamā‘ah, al-Manhal al-Rawī, p.30. There are three possible linguistic origins for the term sanad: elevation/raise, base/authority, and harshness/strength. See: al-Jawnfūrī, Nawādir al-Hadīth, p.37.
 Al-Thanawī, Kashfshāf Istilihāt al-Funūn wa al-‘Ulūm, p.984; Abū Ghuddah, al-Isnād min al-Dīn, p.14.
 Ibn al-‘Ajamī, Hashiyah ‘alā Tadrīb al-Rāwī, vol.3, p.89. For more on both terms, see: al-Suyūtī, Tadrīb al-Rāwī [with editor’s footnotes], vol.2, pp.31-33; al-Qārī, Sharh Sharh al-Nukhbah, pp.159-160; al-Jawnfūrī, Nawādir al-Hadīth, pp.37-38; Tāriq ibn ‘Awad Allāh, Sharh Lughat al-Muhaddith, pp.62-63. Be it as it may, as Shams al-Dīn al-Sakhāwi (d. 902 AH) explains, this is a flexible matter. See: al-Sakhāwī, Fath al-Mughīth, vol.1, p.23.
 Al-Bukhārī, al-Jāmi‘ al-Musnad al-Sahīh, vol.1 p.33.
 Abū Ghuddah, al-Isnād min al-Dīn, p.14.
 Al-Tirmidhī, al-Sunan, vol.5, p.414; cf. al-Mizzī, Tuhfat al-Ashrāf, no.6577.
 Ahmad, al-Musnad, vol.3, p.262; cf. Ibn Hajar, Ithāf al-Maharah, vol.4, p.75/Itrāf al-Musnid al-Mu‘talī, vol.2, p.208.
 In Tadrīb al-Rāwī, Jalāl al-Dīn al-Suyūtī dedicated chapter 92 to the hadiths of those Companions who passed away during the Prophet’s lifetime. See: al-Suyūtī, Tadrīb al-Rāwī, vol.5, pp.635-636. He is said to have also authored a book on the subject. See: Hājī Khalīfah, Kashf al-Zunūn, vol.2, p.1683.
 Fallātah, al-Wad‘ fī al-Hadīth, vol.2, pp.15-19.
 See, for instance, al-Bukhārī, al-Jāmi‘ al-Musnad al-Sahīh, vol.1, p.29; al-A‘żamī, On Schacht’s Origins of Muhammadan Jurisprudence, p.155.
 Fallātah, al-Wad‘ fī al-Hadīth, vol.2, p.19.
 Al-Barā’ ibn ‘Āzib said, “We did not hear from the Prophet everything we narrate from him directly. We heard from him, and our companions would also narrate to us [from him]. But we would not lie.” See: Ahmad, al-‘Ilal wa Ma‘rifat al-Rijāl, vol.2, p.410. Anas ibn Mālik said, “By Allah, we would not lie. We did not know what lying was.” See: al-Fasawī, al-Ma‘rifah wa al-Tārīkh, vol.2, pp.633-634. For a study of the alleged reports of fabrication during the Prophet’s lifetime, see: Abū Ghuddah, Lamahat, pp.56-65.
 On the report of ‘Alī ibn Abī Tālib taking an oath from a narrator before accepting his hadiths, see: al-Bukhārī, al-Tārīkh al-Kabīr, vol.2, p.54.
 Al-Dhahabī, Tadhkirat al-Huffāż, vol.1, p.9.
 Al-Tirmidhī, al-Sunan, vol.3, p.491.
 Mālik, al-Muwatta’, vol.5, p.1403. For an important clarification on these and other similar reports, see: al-Suyūtī, Tadrīb al-Rāwī, vo.2, p.188; al-Sibā‘ī, al-Sunnāh wa Makānatuhā fī al-Tashrī‘ al-Islāmī, pp.85-89.
 Abū Ghuddah, Lamahāt, p.73.
 See: Mullā Khātir, Bid‘at Da‘wā al-I‘timād ‘alā al-Kitāb Dūn al-Sunnāh, p.18.
 Mustafā al-Sibā‘ī enumerates seven factors that prompted the fabrication of hadīths. See: al-Sibā‘ī, al-Sunnah wa Makānatuhā fī al-Tashrī‘ al-Islāmī, pp.96-105.
 There is considerable debate on the interpretation of ‘Fitnah’ in the words of Ibn Sīrīn. Some scholars opine that it refers to the assassination of ‘Uthmān ibn ‘Affān. See: Abū Ghuddah, Lamahāt, p.73. Based on a statement of Ibrāhim al-Nakha‘ī that people only began asking for isnād during the era al-Mukhtār ibn Abī ‘Ubayd al-Thaqafī (d. 67 AH), some argue for a later date. See: Ahmad, al-‘Ilal wa Ma‘rifat al-Rijāl, vol.3, p.380. With variations on the specific date, many contemporary scholars agree that fabrication began around the year 40 AH. Mujīr al-Khatīb explains that sparks of fabrication began during the period of the Successors when the first wave of trials and innovations surfaced; thus, leaving the date abstract so as to include the various opinions is more preferable. See: al-Hasanī, Ma‘rifat Madār al-Isnād, vol.1, p.385. For a study of Orientalist views on the date of the origins of isnād, see: al-A‘żamī, Studies In Early Hadīth Literature, pp.216-217/On Schacht’s Origins of Muhammadan Jurisprudence, pp.166-168; Siddiqi, Hadīth Literature: Its Origins Development and Special Features, pp.79-80.
 Muslim, Introduction to his Sahīh, p.11.
 Al-A‘żamī, Studies In Early Hadīth Literature, p.217.
 Ibid., p.213.
 See: Abū Ghuddah, Lamahāt, p.145. Despite the weakness of a hadith’s chain of transmission, scholars at times would authenticate its contents due to external factors, like inherited practice. For more on this, see: al-Kawtharī, al-Maqālāt, pp.75-78; Abū Ghuddah, al-Ajwibah al-Fādilah, p.228 f.; Brown, Did the Prophet Say It or Not? The Literal, Historical, and Effective Truth of Hadīths in Early Sunnism, p.277; also see Haydar Hasan’s treatise in: al-Nu‘mānī, al-Imām Ibn Mājah wa Kitābuhū al-Sunan, pp.86-90. This brings to mind the priceless observation of Anwar Shāh al-Kashmīrī, “It [Ibn Hajar al-‘Asqalānī’s judgment] is premised only on rules while al-Tirmidhī’s assessment is based on sense and sound intuition, and, truly, this is knowledge. And [rigid] rules are a blind man’s walking stick.” See: al-Kashmīrī, Fayd al-Bārī, vol.6, p.216/vol.4, p.130. But in the same breath, another piece of advice should not escape our attention, “Do not be like the one to whom it is said: you remembered one thing, but you forgot many things.” See: Ibid. [al-Mīrathī, al-Badr al-Sārī], vol.4, p.130.
 Muslim, Introduction to his Sahīh, p.11.
 Al-Baghdādī, Sharaf Ashāb al-Hadīth, p.42
 Abū Ghuddah, Lamahāt, pp.143-145.
 See: al-Sarrāj, Masāri‘ al-‘Ushshāq; Siddique, Hadīth Literature, p.84. Scholars like al-Jāhiz (235 AH), Abū al-Faraj al-Asfahānī (d. 356 AH), and Ibn al-Jawzī (d. 597 AH) even cite isnāds for light hearted anecdotes. See: al-A‘żamī, On Schacht’s Origins of Muhammadan Jurisprudence, p.154.
 Al-Asad, Masādir al-Shi‘r al-Jāhilī, pp.255 f.; al-A‘żamī, Studies In Early Hadīth Literature, p.212. Schoeler negates the possibility of isnāds being used by pre-Islāmic poets. See: Cook, The Opponents of the Writing of Tradition in Early Islam, pp.511-512.
 Horovits, Alter Und Ursprung des Isnad, Der Islam, VIII, pp.39-47; Cook, The Opponents of the Writing of Tradition in Early Islam, pp.510- 512. Horovits did not provide evidence to show that these chains were not later fabrications. He does, however, write, “In the Talmudic literature, there is no idea of a chronological method, and the oldest extant work attempting such an arrangement was composed after 885 AD—more than a century later than the earliest Islamic work on isnād-critique. From this fact, and from the fact that the important Jewish works had been composed in the Islamic dominions, it may be inferred that the historical interest was due to the Islamic influence [emphasis mine].” See: Horovits, Alter, p.47; Siddiqi, Hadīth Literature, p.81, 150.
 See: Siddiqi, Hadīth Literature, pp.78-79, 81.
 Ibn Hazm, al-Fisal, vol.2, pp.67-70.
 Sprenger, A Biographical Dictionary of Persons Who Knew Mohammad, vol.1, p.1. There is a degree of exaggeration in these figures, but there is no doubt that the Muslim civilization is peerless in this accomplishment. See: Abū Ghuddah, Lamahāt, p.163.
 Abbott, Studies in Arabic Literary Papyri II, p.66; Brown, Hadīth, p.219.
 It is difficult to determine the exact number of individual hadiths. Nevertheless, Sālih Ahmad al-Shāmī gathered the hadiths of 14 major Hadīth compilations: the six canonical books, Muwatta’ Mālik, Musnad Ahmad, the Sunans of al-Dārimī and al-Bayhaqī, the Sahīhs of Ibn Khuzaymah and Ibn Hibbān, al-Mustadrak of al-Hākim, and al-Mukhtārah of al-Diyā’ al-Maqdisī. In total, he gathered 114,194 hadīths, and after removing repetitions, there remained 28,430 hadīths. It should be noted that he did not regard the narration of two different Companions for an identical hadith as a repetition. See: al-Shāmī, Ma‘ālim al-Sunnah al-Nabawiyyah, p.9.
 Al-Rāzī, al-Jarh wa al-Ta‘dīl, vol.1, p.261
 al-A‘żamī, Studies In Early Hadīth Literature, p.302.
 Al-Baghdādī, Tārīkh Baghdād, vol.2, p.340.
 Abū Musā, Khasā’is al-Musnad, p.21.
 Shākir, Footnotes on Khasā’is al-Musnad, p.21; Abū Ghuddah, Footnotes on Mabādī’ ‘Ilm al-Hadīth wa Usūluh, p.55; al-A‘żamī, Studies In Early Hadīth Literature, p.303.
 See: al-Tabarī, Tārīkh al-Umam wa al-Mulūk, vol.1, pp. 7-8; al-Kawtharī, al-Maqālāt, p.404. Ibn Hajar writes, “Most Hadīth scholars of the past—from 200 AH onwards—believed that citing a hadith with its chain of transmission absolved them of the responsibility [of analyzing it].” See: Ibn Hajar, Lisān al-Mīzān, vol.4 p.125; cf. ‘Awwāmah, Footnotes on Tadrīb al-Rāwī, vol.3, pp.519-520. Zayn al-Dīn al-‘Irāqī explains that although citing a hadith alongside its problematic chain without expounding on its defects is reprehensible, to do so without citing its chain at all is worse. See: al-‘Irāqī, Sharh al-Tabsirah wa al-Tadhkirah, vol.1, p.313; Brown, Did the Prophet Say It or Not? The Literal, Historical, and Effective Truth of Hadīths in Early Sunnism, pp.281-282.
 Abū Ghuddah, al-Ajwibah al-Fādilah, p.238.