The Prophet ﷺ said, "Whoever kills a person under a covenant of protection will not smell the fragrance of Paradise, though its fragrance can be detected from a distance of forty years' travel."
عن النبي ﷺ قال: من قتل نفسا معاهدا لم يرح رائحة الجنة، وإن ريحها ليوجد من مسيرة أربعين عاما.
Bukhari related it in the Book of Blood Money (6914), from Qays bin Hafs, who said, "Abdul-Wahid (that is, Ibn Ziyad) narrated to us, Hasan (that is, Ibn Amr Fuqaymi) narrated to us, Mujahid narrated to us, from Abdullah bin Amr," and he mentioned it.