‏الإيمان : Hadeeth No:116 It is reported on the authority of Ibn 'Umar that the Prophet (may peace and blessings be upon him) observed: When a man calls his brother an unbeliever, it returns (at least) to one of them....

‏فضائل الصحابة‏ : Hadeeth No:6133 Abu Huraira reported: Since I heard three things from Allaah's Messenger (sallAllaahu alayhi wa sallam) my love for Banu Tamim is never on the decline (and these things are): I heard Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying about them that they would put up stout resistance agains...