Famous Bakri scholar Muhammad Ibn Ahmad al-Dhahabi (exp. 748 A.H.) in his book “Seyar A’laam al-Nubalaa” vol. 14, p. 133, after praising the celebrated scholar of the Ahle Tasannun Abu Abd al-Rahman Ahmad Ibn Shuaib al-Nasaai (exp. 303 A.H.), writes:
“In the third century of Hijri, there was no scholar more learned than Nasaai. He was more brilliant than most of his illustrious contemporaries like Muslim, Abu Dawood and Tirmidhi. The only problem with him was that he had strains of Shiism in his thoughts, of which was his enmity against the enemies of Imam Ali (a.s.) like Moaviyah, Amr Aas, etc. May Allah pardon him!”