[3] Having been a soldier under the Abbasid Caliphate, he received the nicknamed Qassab or "the butcher" due to his skill on the battlefield and the large number of opponents he slayed.
[5][6][7] In his exegesis of the Qur'an, he would often refer to linguistic arguments in order to prove his point.
[1] Qassab was noted among Muslim theologians as holding the view that the testimony of a convicted criminal could later be accepted in unrelated cases if they performed a public repentance for their own crime.
[8] Like Ibn Hazm who would come after him, Qassab did not accept the Hadith regarding rejection of the convict's testimony as authentically linked to the Islamic prophet Muhammad.
Qassab authored an exegesis of the Qur'an centered on its applications in Islamic law.