Hadith 3166
Narrated `Abdullah bin `Amr: The Prophet said, "Whoever killed a person having a treaty with the Muslims, shall not smell the smell of Paradise though its smell is perceived from a distance of forty years."
Hadith 5991
Narrated `Abdullah bin `Amr: The Prophet said, "Al-Wasil is not the one who recompenses the good done to him by his relatives, but Al-Wasil is the one who keeps good relations with those relatives who had severed the bond of kinship with him."
Hadith 6914
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).