Hadith on Islam: Whoever fights the Muslims or lies against them is not one of them

Abu Huraira reported: The Messenger of Allah, peace be upon him, said, “He who took up arms against us is not one of us; and he who acted dishonestly towards us is not one of us.”
[Sahih Muslim, Book 1, Number 182]

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

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