The isnad (chain of transmission) of hadith, as a chain of narrators, plays a key role in the authentication and preservation of the text of hadith, and throughout history, attention to it among Islamic sects has experienced fluctuations. Among these, some Sunni scholars, including Dr. Nasser al-Qaffari in his book "Usul Madhhab al-Shi'ah" (Principles of the Shi'a School), have considered attention to the isnad of hadith to be exclusive to Sunnis and have emphasized the fabricated nature of many of the isnads of Shi'a hadith. This article, written with a descriptive-analytical method and using library resources, has been prepared in response to this doubt. Based on the research findings, there is ample evidence of attention to the isnad in Shi'ism. The Infallible Imams (a.s.) have always encouraged Shi'as to verify the authenticity of narrations. Furthermore, Shi'a scholars have long had numerous writings in the science of Rijal (biography of narrators), which indicates their attention to examining the trustworthiness and backgrounds of hadith narrators. In contrast, a century of struggle against hadith among Sunnis and the confessions of their scholars and narrators to the numerous fabrications in Sunni hadith invalidate the claim of intense attention to hadith and its isnad. Therefore, there remains no doubt that this doubt stems from ignorance or a biased disregard for historical evidence and documentation.
Based on the findings of the research, there are many evidences of attention to Sindh in Shia. The infallible imams have always encouraged Shiites to verify hadiths. Also, Shiite scholars have long written numerous works on the science of men, which shows their interest in investigating the reliability and records of hadith narrators. On the other hand, a century of fighting against hadith among the Sunnis and the confessions of their scholars and narrators to many fakes in the hadith of the Sunnis nullifies the claim of intense attention to hadith and chain of transmission. Therefore, there is no doubt that this doubt is caused by ignorance or biased disregard of historical evidence and documents.