صحيح مسلم
Sahih Muslim
كتاب الإيمان
The Book of Faith
باب بَيَانِ حَالِ إِيمَانِ مَنْ قَالَ لأَخِيهِ الْمُسْلِمِ يَا كَافِرُ:
Chapter: Clarifying the condition of faith for one who says to his muslim brother: "O Kafir (Disbeliever)."
Hadith 60
This hadith is listed as number 216 in Maktaba Shamila
وحَدَّثَنَا يَحْيَي بْنُ يَحْيَي التَّمِيمِيُّ ، وَيَحْيَي بْنُ أَيُّوبَ ، وَقُتَيْبَةُ بْنُ سَعِيدٍ ، وَعَلِيُّ بْنُ حُجْرٍ جَمِيعًا ، عَنْ إِسْمَاعِيل بْنِ جَعْفَرٍ ، قَالَ يَحْيَي بْنُ يَحْيَي : أَخْبَرَنَا إِسْمَاعِيل بْنُ جَعْفَرٍ ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ ، أَنَّهُ سَمِعَ ابْنَ عُمَرَ ، يَقُولُ : قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " أَيُّمَا امْرِئٍ قَالَ لِأَخِيهِ : يَا كَافِرُ ، فَقَدْ بَاءَ بِهَا أَحَدُهُمَا ، إِنْ كَانَ كَمَا قَالَ ، وَإِلَّا رَجَعَتْ عَلَيْهِ " .
It is reported on the authority of Ibn 'Umar that the Messenger of Allah (ﷺ) (may peace and blessings be upon him) said: Any person who called his brother: or unbeliever (has in fact done an act by which this unbelief) would return to one of them. If it were so, as he asserted (then the unbelief of man was confirmed but if it was not true), then it returned to him (to the man who labeled it on his brother Muslim).
