(4) باب سِبَابُ الْمُسْلِمِ فُسُوقٌ وَقِتَالُهُ كُفْرٌ
It was narrated from Abu Hurairah that the Prophet (ﷺ) said:
"Verbally abusing a Muslim is Fusuq (disobedience) and fighting himisKufr (ungratefulness to Allah)." (JA)
Reference (JA): Sunan Ibn Majah 3940 (JA)
In-book reference (JA): Book 36, Hadith 15 (JA)
English translation (JA): Vol. 5, Book 36, Hadith 3940 (JA)