(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).'" (FR)
Reference (FR): Sunan Ibn Majah 3939 (FR)
In-book reference (FR): Book 36, Hadith 14 (FR)
English translation (FR): Vol. 5, Book 36, Hadith 3939 (FR)