Chapter 1: Introduction
Amr bin Alī Abū Hafs narrated to us, he said I heard Yahyā bin Sa’īd, he said: ‘I asked Sufyān ath-Thawrī, Shu’bah, Mālik, and Ibn Uyaynah about a man who is not reliable (Thabt) in Ḥadīth, and someone comes and asks me about him, and they said: ‘Inform [others] against him that he is not reliable’.’
Sahih Muslim Introduction 35