Ibn Taymiyyah, a 7th-century scholar, believed in the permissibility of insulting and belittling the character of Ali (peace be upon him) and harbored enmity towards him. In his works, including *Majmu' Fatawa*, *Minhaj al-Sunnah*, and other writings, Ali (peace be upon him) is described as tyrannical, arrogant, oppressive, unjust, bloodthirsty, and a servant of power and the world. All narrations that articulate his virtues, according to Ibn Taymiyyah, are deemed weak, contrary to the apparent meaning, or requiring interpretation. In these texts, his position of caliphate is questioned, and his wars are considered unlawful.

According to Sunni sources, a Nasibi is one who belittles the character of Ali (peace be upon him) and engages in enmity and hostility towards him in both word and deed. Allameh Kuthar asserts that Ibn Taymiyyah's insults, hostility, and insolence towards Amir al-Mu'minin (peace be upon him) have no precedent in Islamic communities, even among the Kharijites. Asqalani believes that Ibn Taymiyyah was a Nasibi and harbored animosity towards Ali (peace be upon him). Omar Bitar warns Muslims not to be deceived by the whispers of the devil (Ibn Taymiyyah). Dhahabi cautions Ibn Taymiyyah to cease his innovations, accusations, and insults against Ali (peace be upon him). Husni Dimashqi deems the excommunication of Ibn Taymiyyah necessary by Islamic scholars, as he has shown insolence toward the caliph of the Messenger of Allah (peace be upon him and his family).