Muslim

And we did not know anyone among the Imams of the Salaf, from those who used the reports and examined the authenticity and weakness of the chains of narration, like Ayyub al-Sakhtiyani, Ibn ‘Awn, Malik ibn Anas, Shu‘bah ibn al-Hajjaj, Yahya ibn Sa‘id al-Qattan, ‘Abd al-Rahman ibn Mahdi, and those after them from the people of hadith, who investigated the place of hearing in the chains of narration as was claimed by the one whose statement we described earlier. Rather, the examination by those among them who examined, was regarding the hearing of the narrators of hadith from those from whom they narrated, if the narrator was known for tadlis in hadith and was famous for it. Then, at that point, they would investigate his hearing in his narration and examine it.