From Sahih Bukhari (Hadith 5778):
Narrated Abu Huraira:The Prophet (ﷺ) said, "Whoever purposely throws himself from a mountain and kills himself, will be in the (Hell) Fire falling down into it and abiding therein perpetually forever; and whoever drinks poison and kills himself with it, he will be carrying his poison in his hand and drinking it in the (Hell) Fire wherein he will abide eternally forever; and whoever kills himself with an iron weapon, will be carrying that weapon in his hand and stabbing his `Abdomen with it in the (Hell) Fire wherein he will abide eternally forever
Reference: Bukhari 5778