Hadith on War: Whoever fights or deceives believers is not a true Muslim

Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said, “Whoever raises arms against us is not one of us. Whoever deceives us is not one of us.

Source: Ṣaḥīḥ Muslim 101

Grade: Sahih (authentic) according to Muslim

عَنْ أَبِي هُرَيْرَةَ أَنَّ رَسُولَ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ مَنْ حَمَلَ عَلَيْنَا السِّلَاحَ فَلَيْسَ مِنَّا وَمَنْ غَشَّنَا فَلَيْسَ مِنَّا

101 صحيح مسلم كتاب الإيمان باب قول النبي صلى الله عليه وسلم من غشنا فليس منا