Suicide is a major sin. The Prophet (peace and blessings of Allaah be upon him) stated that the one who commits suicide will be punished with something like that with which he killed himself.
Abu Hurayrah (may Allaah be pleased with him) narrated that the Prophet (peace and blessings of Allaah be upon him) said:
“Whoever throws himself down from a mountain and kills himself will be in the Fire of Hell, throwing himself down therein for ever and ever. Whoever takes poison and kills himself, his poison will be in his hand and he will be sipping it in the Fire of Hell for ever and ever. Whoever kills himself with a piece of iron, that piece of iron will be in his hand and he will be stabbing himself in the stomach with it in the Fire of Hell, for ever and ever.”
Narrated by al-Bukhaari, 5442; Muslim, 109.
It was narrated from Thaabit ibn al-Dahhaak (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said:
“Whoever kills himself with something in this world will be punished with it on the Day of Resurrection.”
Narrated by al-Bukhaari, 5700; Muslim, 110.
It was narrated that Jundub ibn ‘Abd-Allaah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said:
“Among those who came before you there was a man who was wounded and he panicked, so he took a knife and cut his hand with it, and the blood did not stop flowing until he died. Allaah said: ‘My slave hastened to bring about his demise; I have forbidden Paradise to him.”
Narrated by al-Bukhaari, 3276; Muslim, 113.