Allah said,

﴿وَلاَ تَقْتُلُواْ أَنفُسَكُمْ﴾

(And do not kill yourselves.) by committing Allah's prohibitions, falling into sin and eating up each other's property unjustly,

﴿إِنَّ اللَّهَ كَانَ بِكُمْ رَحِيماً﴾

(Surely, Allah is Most Merciful to you.) in what He commanded you and prohibited you from. Imam Ahmad recorded that `Amr bin Al-`As said that when the Prophet sent him for the battle of Dhat As-Salasil, "I had a wet dream during a very cold night and feared that if I bathed, I would die. So I performed Tayammum (with pure earth) and led my company in the Dawn prayer. When I went back to the Messenger of Allah , I mentioned what had happened to me and he said,

«يَا عَمْرُو صَلَّيْتَ بِأَصْحَابِكَ وَأَنْتَ جُنُب»

(O `Amr! Have you led your people in prayer while you were in a state of sexual impurity) I said, 'O Messenger of Allah! I had a wet dream on a very cold night and feared that if I bathed I would perish, and I remembered Allah's statement,

﴿وَلاَ تَقْتُلُواْ أَنفُسَكُمْ إِنَّ اللَّهَ كَانَ بِكُمْ رَحِيماً﴾

(And do not kill yourselves. Surely, Allah is Most Merciful to you). So I performed Tayammum and prayed.' The Messenger of Allah smiled and did not say anything.'' This is the narration reported by Abu Dawud. Ibn Marduwyah mentioned this honorable Ayah and then reported that Abu Hurayrah said that the Messenger of Allah said,

«مَنْ قَتَلَ نَفْسَهُ بَحَدِيدَةٍ، فَحَدِيدَتُهُ فِي يَدِهِ، يَجَأُ بِهَا بطْنَهُ يَوْمَ الْقِيَامَةِ فِي نَارِ جَهَنَّمَ، خَالِدًا مُخَلَّدًا فِيهَا أَبَدًا، ومَنْ قَتَلَ نَفْسَهُ بِسُمَ فَسُمُّهُ فِي يَدِهِ، يَتَحَسَّاهُ فِي نَارِ جَهَنَّمَ، خَالِدًا مُخَلَّدًا فِيهَا أَبَدًا، وَمَنْ تَرَدَّى مِنْ جَبَلٍ فَقَتلَ نَفْسَهُ، فَهُوَ مُتَرَدَ فِي نَارِ جَهَنَّمَ، خَالِدًا مُخَلَّدًا فِيهَا أَبَدًا»

(Whoever kills himself with an iron tool, then his tool will be in his hand and he will keep stabbing himself with it in the Fire of Jahannam, forever and ever. Whoever kills himself with poison, then his poison will be in his hand and he will keep taking it in the Fire of Jahannam forever and ever. Whoever kills himself by throwing himself from a mountain, will keep falling in the Fire of Jahannam forever and ever.) This Hadith was also collected in the Two Sahihs. Abu Qilabah said that Thabit bin Ad-Dahhak said that the Messenger of Allah said,

«مَنْ قَتَلَ نَفْسَهُ بِشَيْءٍ، عُذِّبَ بِهِ يَوْمَ الْقِيَامَة»

(Whoever kills himself with an instrument, will be punished with it on the Day of Resurrection.) This Hadith was collected by the Group. This is why Allah said,

﴿وَمَن يَفْعَلْ ذلِكَ عُدْوَناً وَظُلْماً﴾

(And whoever commits that through aggression and injustice, ) meaning, whoever commits what Allah has forbidden for him transgression and injustice - while knowing that it is forbidden for him, yet he still dares to commit it,

﴿فَسَوْفَ نُصْلِيهِ نَاراً﴾

(We shall cast him into the Fire,). This Ayah carries a stern warning and a truthful promise. Therefore, every sane person should beware of it, those who hear the speech with full comprehension.