Good Manners and Form (Al-Adab)

Bukhari :: Book 8 :: Volume 73 :: Hadith 70

Narrated 'Abdullah:

Allah's Apostle said, "Abusing a Muslim is Fusuq (i.e., an evil-doing), and killing him is Kufr (disbelief)."

Source materials are from the University of Southern California MSA site
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