Sahih al-Bukhari, Book 23, Hadith 117 (In-Book) ⓘ

Narrated Thabit bin Ad-Dahhak: The Prophet (p.b.u.h) said, "Whoever intentionally swears falsely by a religion other than Islam, then he is what he has said, (e.g. if he says, 'If such thing is not true then I am a Jew,' he is really a Jew). And whoever commits suicide with piece of iron will be punished with the same piece of iron in the Hell Fire." Narrated Jundab the Prophet said, "A man was inflicted with wounds and he committed suicide, and so Allah said: My slave has caused death on himself hurriedly, so I forbid Paradise for him."

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، حَدَّثَنَا خَالِدٌ، عَنْ أَبِي قِلاَبَةَ، عَنْ ثَابِتِ بْنِ الضَّحَّاكِ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ مَنْ حَلَفَ بِمِلَّةٍ غَيْرِ الإِسْلاَمِ كَاذِبًا مُتَعَمِّدًا فَهُوَ كَمَا قَالَ، وَمَنْ قَتَلَ نَفْسَهُ بِحَدِيدَةٍ عُذِّبَ بِهِ فِي نَارِ جَهَنَّمَ ‏"‏‏.‏ وَقَالَ حَجَّاجُ بْنُ مِنْهَالٍ حَدَّثَنَا جَرِيرُ بْنُ حَازِمٍ، عَنِ الْحَسَنِ، حَدَّثَنَا جُنْدَبٌ ـ رضى الله عنه ـ فِي هَذَا الْمَسْجِدِ فَمَا نَسِينَا، وَمَا نَخَافُ أَنْ يَكْذِبَ جُنْدَبٌ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ كَانَ بِرَجُلٍ جِرَاحٌ فَقَتَلَ نَفْسَهُ فَقَالَ اللَّهُ بَدَرَنِي عَبْدِي بِنَفْسِهِ حَرَّمْتُ عَلَيْهِ الْجَنَّةَ ‏"‏‏.‏