question #1 Sahih Muslim Introduction 48, Introduction, Narration 47 : What is the significance of the chain of narrators in the authentication of hadiths?

Hajjāj narrated to me, he said Ahmad- and he is Ibn Yūnus- narrated to me, Zā’idah narrated to us, on authority of Mansūr and al-Mughīrah, on authority of Ibrāhīm that al-Hārith was imputed.