Sunan Ibn Majah 3939
سنن ابن ماجه#3939SahihIt was narrated from Ibn Mas’ud that the Messenger of Allah (ﷺ) said:“Verbally abusing a Muslim is Fusuq disobedience and fighting him is Kufr (ungratefulness to Allah).’”
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 36:14