1437 - He said: Abu 'Abd Allah narrated to us, he said: Waki' and 'Abd al-Rahman narrated to us, from Sufyan, from Zubayd, from Abu Wa'il, from 'Abd Allah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Reviling a Muslim is an act of defiance (fisq), and fighting him is an act of disbelief (kufr)." 'Abd al-Rahman said in his narration: I said to Abu Wa'il: Did you hear Ibn Mas'ud narrate it from the Prophet (peace be upon him)? He said: Yes.