Sahih al-Bukhari 7070
Sahih al-Bukhari · Book 92: Afflictions and the End of the World · “Whosoever takes up arms against us, is not from us.”
Narrated `Abdullah bin `Umar:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ ، أَخْبَرَنَا مَالِكٌ ، عَنْ نَافِعٍ ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَنْ حَمَلَ عَلَيْنَا السِّلاَحَ فَلَيْسَ مِنَّا " .
Allah's Messenger (ﷺ) said, "Whoever takes up arms against us, is not from us."