This is one of Imam Muslim’s Greatest Achievements

It is one of the greatest achievements of Imam Muslim (may Allah have mercy on him) that he narrated a single hadith not only through the chain of one of his teachers but also through the chains of other teachers. Furthermore, in the chain above, he included narrations from multiple transmitters who reported from the same teacher or various teachers. At the highest level, if the same hadith had been narrated by more than one Companion, he would also include those narrations from different chains. If a researcher today were to compile all the chains that Imam Muslim recorded for a single hadith, it would become clear that Imam Muslim did not merely rely on one teacher and that teacher’s teacher, but rather he visited multiple people who had narrated that hadith from the same teacher. He listened to the same hadith separately from various students (Tabi‘in) of that teacher who narrated it at different times and authenticated it through them. In doing so, he clarified that the teachers who narrated the same hadith consistently with identical wording in front of different audiences at various times were in fact highly reliable in terms of memorization and precision, and their narration is authentic. He also verified the reliability of those above his teachers by gathering their narrations through multiple narrators. Often, he compiled the narrations of different Companions who transmitted from the Prophet Muhammad ﷺ and presented them as supporting evidence. For each of them, he included corroborating chains (mutaba‘at), confirmed their reliability through mutual cross-verification, and selected only those ahadith that were flawless in both precision and retention. Such meticulous effort would be difficult even for the most authoritative court or verification institution in the largest of cases.

Even if there was a very minor difference in the words or the chain—such as the difference between “haddathana” and “akhbarana”—he preserved it. He also noted even the slightest variations in the text. In this way, Sahih Muslim became an exceptional practical model of comparison and verification between hadith chains and texts.