Sunan Ibn Majah 3941
سنن ابن ماجه#3941SahihIt was narrated from Sa’d that the Messenger of Allah (ﷺ) said:“Verbally abusing a Muslim is Fusuq (disobedience) and fighting him is Kufr.”
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
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih
In-book reference: 36:16