Sahih Muslim Book 1, Hadith Number 208.

Chapter : Suicide is the gravest sin.

It is reported on the authority of Hasan: Jundab b. ‘Abdullah al-Bajali narrated this hadith in this mosque which we can neither forget and at the same time we have no apprehension that Jundab could attribute a lie to the Messenger of Allah (may peace be upon him). He (the Holy Prophet) observed: A person belonging to the people of the past suffered from a boil, and then the rest of the hadith was narrated.