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Bulugh al-Maram #1685
كتاب الجامع
وَعَنْ اِبْنِ مَسْعُودٍ - رضى الله عنه - قَالَ: قَالَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -«سِبَابُ اَلْمُسْلِمِ فُسُوقٌ, وَقِتَالُهُ كُفْرٌ» مُتَّفَقٌ عَلَيْهِ.
Ibn Mas'ud (RAA) narrated that the Messenger of Allah (ﷺ) said:
insulting a Muslim is disobedience to Allah, and fighting with him is Kufr (disbelief).” Agreed upon.
وَعَنْ اِبْنِ مَسْعُودٍ - رضى الله عنه - قَالَ: قَالَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -"سِبَابُ اَلْمُسْلِمِ فُسُوقٌ, وَقِتَالُهُ كُفْرٌ" مُتَّفَقٌ عَلَيْهِ.
insulting a Muslim is disobedience to Allah, and fighting with him is Kufr (disbelief).” Agreed upon.
— Bulugh al-Maram, Hadith 1685