It was narrated from Shu'bah who said: "I said to Hammad: 'I heard Mansur, and Sulaiman, and Zubaid narrating from Abu Wa'il, from 'Abdullah, that the Messenger of Allah [SAW] said: "Defaming a Muslim is evildoing and fighting him is Kufr." - Who are you worried about? Are you worried about Mansur? Are you worried about Zubaid? Are you worried about Sulaiman?' He said: 'No, but I am worried about Abu Wa'il.'"