(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)." (RU)
Reference (RU): Sunan Ibn Majah 3940 (RU)
In-book reference (RU): Book 36, Hadith 15 (RU)
English translation (RU): Vol. 5, Book 36, Hadith 3940 (RU)