(4) باب سِبَابُ الْمُسْلِمِ فُسُوقٌ وَقِتَالُهُ كُفْرٌ
It was narrated from Ibn Mas'ud that the Messenger of Allah (ﷺ)said:
"Verbally abusing a Muslim is Fusuq disobedience and fightinghim is Kufr (ungratefulness to Allah).'" (DE)
Reference (DE): Sunan Ibn Majah 3939 (DE)
In-book reference (DE): Book 36, Hadith 14 (DE)
English translation (DE): Vol. 5, Book 36, Hadith 3939 (DE)