Sayyiduna Ibn Mas'ud (may Allah be pleased with him) also narrates that the Messenger of Allah (peace and blessings be upon him) said: To revile a Muslim is wickedness and to fight him is disbelief, and the sanctity of a Muslim is like the sanctity of his blood.
Hadith Referenceالفتح الربانی / كتاب المدح والدم / 10127
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«صحيح، أخرجه ابويعلي: 5119، والطيالسي: 306 ، (انظر مسند أحمد ترقيم الرسالة: 4262 ترقیم بيت الأفكار الدولية: 4262»
Brief Explanation
Benefits: … These blessed ahadith are a severe warning for those whose tongues have become accustomed to obscene speech and idle talk, foul language and abusive words, cursing and swearing, and who do not bother to think before uttering a taunt about someone. For example, using abusive language about someone's mother or sister, calling someone illegitimate (haraami), shameless (be-ghayrat), accursed (la‘nati), or addressing them with bad nicknames, etc. Such people are sinful (fasiq) and wicked (fajir).
Hafiz Ibn Hajar rahimahullah said: The application of the term "kufr" (disbelief) is a manner of severity, the purpose of which is to urge the listener to refrain from such actions. It can also be said that the application of "kufr" is by way of resemblance, because in reality, such actions are the deeds of disbelievers. A specific reason for this blessed hadith has also been mentioned, as Imam Baghawi rahimahullah and Imam Tabarani rahimahullah state: Sayyiduna Amr ibn Nu‘man ibn Muqarrin Muzani radi Allahu anhu says: The Messenger of Allah sallallahu alayhi wa sallam went to a gathering of the Ansar, and among them was an Ansari man who was known for foul language and cursing. Upon arriving, the Prophet sallallahu alayhi wa sallam said: ((Sibaab al-muslim akhaahu fusooq, wa qitaaluhu kufr.)) … "For a Muslim to abuse his brother is wickedness (fisq), and to fight him is disbelief (kufr)." Upon hearing this, that man said: By Allah! From now on, I will never abuse anyone. (Fath al-Bari)
This is the value and status of a believer: his wealth and honor are as respected as his very existence.