We witnessed along with Messenger of Allah ﷺ the Khaibar (campaign). Messenger of Allah ﷺ told his companions about a man who claimed to be a Muslim, "This man is from the people of the Fire." When the battle started, the man fought very bravely and received a great number of wounds and got crippled. On that, a man from among the companions of the Prophet ﷺ came and said, "O Allah's Apostle! Do you know what the man you described as of the people of the Fire has done? He has fought very bravely for Allah's Cause and he has received many wounds." The Prophet ﷺ said, "But he is indeed one of the people of the Fire." Some of the Muslims were about to have some doubt about that statement. So while the man was in that state, the pain caused by the wounds troubled him so much that he put his hand into his quiver and took out an arrow and committed suicide with it. Off went some men from among the Muslims to Messenger of Allah ﷺ and said, "O Messenger of Allah ﷺ! Allah has made your statement true. So-and-so has committed suicide." Messenger of Allah ﷺ said, "O Bilal! Get up and announce in public: None will enter Paradise but a believer, and Allah may support this religion (Islam) with a wicked man." (Using translation from Bukhārī 6606)
شَهِدْنَا مَعَ رَسُولِ اللهِ ﷺ خَيْبَرَ فَقَالَ رَسُولُ اللهِ ﷺ لِرَجُلٍ مِمَّنْ يَدَّعِي الْإِسْلَامَ هَذَا مِنْ أَهْلِ النَّارِ فَلَمَّا حَضَرَ الْقِتَالُ قَاتَلَ الرَّجُلُ أَشَدَّ الْقِتَالِ حَتَّى كَثُرَتْ بِهِ الْجِرَاحُ فَأَثْبَتَتْهُ فَجَاءَ رَجُلٌ مِنْ أَصْحَابِ رَسُولِ اللهِ ﷺ فَقَالَ يَا رَسُولَ اللهِ أَرَأَيْتَ الرَّجُلَ الَّذِي ذَكَرْتَ أَنَّهُ مِنْ أَهْلِ النَّارِ قَدْ وَاللهِ قَاتَلَ فِي سَبِيلِ اللهِ أَشَدَّ الْقِتَالِ وَكَثُرَتْ بِهِ الْجِرَاحُ؟ فَقَالَ رَسُولُ اللهِ ﷺ أَمَا إِنَّهُ مِنْ أَهْلِ النَّارِ وَكَادَ بَعْضُ النَّاسِ يَرْتَابُ فَبَيْنَا هُوَ عَلَى ذَلِكَ وَجَدَ الرَّجُلُ أَلَمَ الْجِرَاحِ فَأَهْوَى بِيَدِهِ إِلَى كِنَانَتِهِ فَاسْتَخْرَجَ مِنْهَا سَهْمًا فَانْتَحَرَ بِهَا فَاشْتَدَّ رِجَالٌ مِنَ الْمُسْلِمِينَ إِلَى رَسُولِ اللهِ ﷺ فَقَالُوا يَا رَسُولَ اللهِ قَدْ صَدَّقَ اللهُ حَدِيثَكَ قَدِ امْتُحِنَ فُلَانٌ فَقَتَلَ نَفْسَهُ فَقَالَ رَسُولُ اللهِ ﷺ يَا بِلَالُ قُمْ فَأَذِّنْ لَا يَدْخُلُ الْجَنَّةَ إِلَّا مُؤْمِنٌ وَإِنَّ اللهَ يُؤَيِّدُ الدِّينَ بِالرَّجُلِ الْفَاجِرِ