Hadith 4745

(حديث مرفوع) حَدَّثَنَا يَعْلَى بْنُ عُبَيْدٍ ، حَدَّثَنَا فُضَيْلٌ يَعْنِي ابْنَ غَزْوَانَ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ ، قَالَ : قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ " أَيُّمَا رَجُلٍ كَفَّرَ رَجُلًا ، فَإِنْ كَانَ كَمَا قَالَ ، وَإِلَّا فَقَدْ بَاءَ بِالْكُفْرِ " .
It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever calls a person a disbeliever, if he is truly a disbeliever, then it is correct; otherwise, it returns upon the one who said it, and he himself becomes a disbeliever."
Hadith Reference مسند احمد / مسند المكثرين من الصحابة / 4745
Hadith Grading حکم دارالسلام: إسناده صحيح