Sahih Bukhari Volume 5, Book 64, Hadith 4206

حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، قَالَ أَخْبَرَنِي سَعِيدُ بْنُ الْمُسَيَّبِ، أَنَّ أَبَا هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ شَهِدْنَا خَيْبَرَ، فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لِرَجُلٍ مِمَّنْ مَعَهُ يَدَّعِي الإِسْلاَمَ ‏"‏ هَذَا مِنْ أَهْلِ النَّارِ ‏"‏‏.‏ فَلَمَّا حَضَرَ الْقِتَالُ قَاتَلَ الرَّجُلُ أَشَدَّ الْقِتَالِ، حَتَّى كَثُرَتْ بِهِ الْجِرَاحَةُ، فَكَادَ بَعْضُ النَّاسِ يَرْتَابُ، فَوَجَدَ الرَّجُلُ أَلَمَ الْجِرَاحَةِ، فَأَهْوَى بِيَدِهِ إِلَى كِنَانَتِهِ، فَاسْتَخْرَجَ مِنْهَا أَسْهُمًا، فَنَحَرَ بِهَا نَفْسَهُ، فَاشْتَدَّ رِجَالٌ مِنَ الْمُسْلِمِينَ، فَقَالُوا يَا رَسُولَ اللَّهِ، صَدَّقَ اللَّهُ حَدِيثَكَ، انْتَحَرَ فُلاَنٌ فَقَتَلَ نَفْسَهُ‏.‏ فَقَالَ ‏"‏ قُمْ يَا فُلاَنُ فَأَذِّنْ أَنَّهُ لاَ يَدْخُلُ الْجَنَّةَ إِلاَّ مُؤْمِنٌ، إِنَّ اللَّهَ يُؤَيِّدُ الدِّينَ بِالرَّجُلِ الْفَاجِرِ ‏"‏‏.‏ تَابَعَهُ مَعْمَرٌ عَنِ الزُّهْرِيِّ‏

Narrated By Abu Huraira : We witnessed (the battle of) Khaibar. Allah's Apostle said about one of those who were with him and who claimed to be a Muslim. "This (man) is from the dwellers of the Hell-Fire." When the battle started, that fellow fought so violently and bravely that he received plenty of wounds. Some of the people were about to doubt (the Prophet's statement), but the man, feeling the pain of his wounds, put his hand into his quiver and took out of it, some arrows with which he slaughtered himself (i.e. committed suicide). Then some men amongst the Muslims came hurriedly and said, "O Allah's Apostle! Allah has made your statement true so-and-so has committed suicide. "The Prophet said, "O so-and-so! Get up and make an announcement that none but a believer will enter Paradise and that Allah may support the religion with an unchaste (evil) wicked man.