Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) delivered a sermon and said: "Indeed, Allah, the Mighty and Majestic, has given everyone who has a right his right. Listen! Allah has laid down obligations, established sunnahs, set limits, made the lawful lawful and the unlawful unlawful, and He laid down the religion and made it easy, gentle and spacious, and did not make it narrow. Listen! There is no faith in one who has no trustworthiness, and no religion in one who has no covenant; and whoever breaks my covenant will not attain my intercession, nor will he come to me at my Pond (al-Hawd)." Listen! Allah, the Mighty and Majestic, has not permitted killing except in three cases: one who apostatises after believing, one who commits adultery while married, or one who kills a soul and is killed in retaliation for his killing. Listen! Have I conveyed?
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11483