Abdullah (b. Mas'ud) reported Allah's Messenger (ﷺ) as saying:
It is not permissible to take the life of a Muslim who bears testimony (to the fact that there is no god but Allah, and I am the Messenger of Allah, but in one of the three cases: the married adulterer, a life for life, and the deserter of his Din (Islam), abandoning the community.
Reference: Sahih Muslim 1676 a In-book : Book 28, Hadith 34 USC-MSA web (English) : Book 16, Hadith 4152 (deprecated)
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