Isnads are an important feature of the genre of Islamic literature known as hadith and are prioritized in the process that seeks to determine if the tradition in question is authentic or inauthentic.
The contemporary view in modern hadith studies, however, is that isnads were commonly susceptible to forgery and so had to be scrutinized before being used to guarantee the transmission of a tradition.
[4] The practice of attributing the transmission of a tradition to a line of known tradents has been compared to the practice of apostolic succession in Christianity, a claim made on the part of Christian churches that their legitimacy in carrying on the traditions of Jesus and the disciples is based on a continuous succession of authorities, especially bishops, from the earliest moments of the Church.
[8] According to Michael Cook:[9]We can then go on to find elements in the Islamic edifice that look like specific borrowings from Judaism ... the chain of transmitters that accompanies an oral account, known on the Muslim side as the isnād, as in "Muḥammad ibn Yūsuf informed us from Sufyān from Abū ʾl-Zinād from Mūsā ibn Abī ʿUthmān from his father from Abū Hurayra from the Prophet who said..." The only other religious culture in which we find such a style of attribution is Judaism, as in “Rabbi Zeriqa said: Rabbi Ammi said: Rabbi Simeon ben Laqish said:...” What was different was that once adopted in Islam the practice was developed much more systematically and applied to a much wider range of material.One Jewish chain of transmission is reiterated in the Quran (5:44).
One of the most common pieces of evidence considered in these discussions is in a statement that has been attributed to the Basran scholar Ibn Sirin (d. 110/728 AD), which states:[11] Lam yakūnū yas’alūna ‘an al-isnād.
Isnads recorded in this era but do not meet this criteria are therefore more likely to be real, as they had not been furnished and shaped according to the emerging editorial standards of hadith scholars (muhaddithin).
[14] Today, isnads are thought to have entered usage three-quarters of a century after Muhammad's death, before which hadith were transmitted haphazardly and anonymously.
[26] The primary advocate of ICMA in the initial stages of the development and application of the method was Motkzi; Motzki believed that the oral transmission of hadith would result in a progressive divergence of multiple versions of the same original report along different lines of transmitters.
By comparing them to pinpoint shared wording, motifs and plots, the original version of a hadith that existed prior to the accrual of variants among different transmitters may be reconstructed.