When a Muslim's blood is lawful

On the authority of Ibn Masʿūd, may Allah be pleased with him, who said: The Messenger of Allah ﷺ said: The blood of a Muslim who testifies that there is no god but Allah and that I am the Messenger of Allah is not lawful except in one of three cases: the married person who commits adultery, a life for a life, and the one who forsakes his religion and separates from the community.