رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 1733
The Book of the Prohibited actions
Prohibition of Calling a Muslim an Infidel
وَعَنْ أَبِي ذَرٍّ رَضِيَ اللَّهُ عَنْهُ أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: مَنِ دَعَا رَجُلاً بِالْكُفْرِ، أَوْ قَالَ: عَدُوَّ اللَّهِ، وَلَيْسَ كَذَلِكَ إِلاَّ حَارَ عَلَيْهِ ((مُتَّفَقٌ عَلَيْهِ)). حار رجع.
Abu Dharr (May Allah be pleased with him) said: I heard the Messenger of Allah (ﷺ) saying, "If somebody accuses another of disbelief or calls him the enemy of Allah, such an accusation will revert to him (the accuser) if the accused is innocent." [Al-Bukhari and Muslim].
Riyad as-Salihin, 1733