Question:
Does fighting with a Muslim make a person a disbeliever (kāfir)?
Source: Fatāwā Amunpuri by Shaykh Ghulam Mustafa Zaheer Amunpuri
Answer:
According to the consensus of Ahl al-Sunnah wa’l-Jamāʿah, committing a major sin (kabīrah), such as fighting with a Muslim, does not expel a believer from Islam.
Prophetic Evidence:
❀ ʿAbdullāh ibn Masʿūd رضي الله عنه narrated that the Messenger of Allah ﷺ said:
سباب المسلم فسوق، وقتاله كفر
“Abusing a Muslim is sinful (fisq), and fighting him is disbelief (kufr).”
(Ṣaḥīḥ al-Bukhārī: 48, Ṣaḥīḥ Muslim: 64)
Here, the term kufr refers to kufr dūna kufr (a lesser form of disbelief), meaning it is a major sin but does not take the perpetrator outside the fold of Islam.
Scholarly Consensus:
❀ ʿAllāmah al-Kirmānī رحمه الله (786 AH):
إن الإجماع من أهل السنة منعقد على أن المؤمن لا يكفر بالقتال ولا بفعل معصية أخرى
“Consensus has been established among Ahl al-Sunnah that a believer does not become a disbeliever by fighting (a Muslim) or by committing any other sin.”
(Sharḥ al-Kirmānī, 1/190)

- Fighting a Muslim is a grave sin and condemned as “kufr” in the ḥadīth.
- However, it is not real disbelief that expels one from Islam, but rather kufr dūna kufr (lesser disbelief).
- The Ummah is unanimous that a believer does not become a kāfir by such sins.