The chain of narrators of a Hadith is called Isnad. In Islamic tradition, a Hadith refers to the sayings, actions, or approvals of the Prophet Muhammad. To ensure the authenticity of a Hadith, it is essential to have a reliable chain of transmission, known as the Isnad.
The Isnad is essentially a list of individuals who have passed the Hadith from one person to another, ultimately tracing it back to the Prophet Muhammad or his companions. Each person in the chain is referred to as a "narrator."
The authenticity of a Hadith heavily depends on the credibility and reliability of the narrators in the Isnad. Scholars meticulously study the chain to determine whether the narrators were trustworthy and whether they actually met each other and transmitted the information accurately.