Narrated 'Abdullah bin 'Amr: The Prophet said, "Whoever killed a Mu'ahid (a person who is granted the pledge of protection by the Muslims) shall not smell the fragrance of Paradise though its fragrance can be smelt at a distance of forty years (of traveling)."
— Sahih Bukhari, Volume 9, Book 83: Blood Money (Ad-Diyat), Hadith #49