It was narrated from Shubah, from Abu Ishaq who said: "I heard Abu Al-Ahwas (narrate) that Abdullah said: Defaming a Muslim is evildoing and fighting him is Kufr." So Aban said to him: "O Abu Ishaq! You heard it only from Abu Al-Ahwas?" He said: "Rather, I heard it from Al-Aswad and Hubairah.