The sanctity of Muslim blood

Arabic

لَا يَحِلُّ دَمُ امْرِئٍ مُسْلِمٍ إِلَّا بِإِحْدَى ثَلَاثٍ: الثَّيِّبُ الزَّانِي، وَالنَّفْسُ بِالنَّفْسِ، وَالتَّارِكُ لِدِينِهِ الْمُفَارِقُ لِلْجَمَاعَةِ.

Translation

The blood of a Muslim is not lawful except in one of three cases: a married person who commits adultery, a life for a life, and one who abandons his religion and splits from the community.

Narrator

ʿAbdullāh ibn Masʿūd

Source

Bukhārī 6878 · Muslim 1676

Commentary

The three are strictly circumscribed capital offences, never vigilante matters — all require a lawful ruler and due process. Nawawī cites this to show how protected the Muslim's life is: the default is sanctity, the exceptions are narrow.