(1) باب الْحُكْمِ فِيمَنِ ارْتَدَّ
Narrated Aisha, Ummul Mu'minin:
The Messenger of Allah (ﷺ) Said: The blood of a Muslim man who testifies that there is no god but Allah and that Muhammad is Allah's Apostle should not lawfully be shed except only for one of three reasons: a man who committed fornication after marriage, in which case he should be stoned; one who goes forth to fight with Allah and His Apostle, in which case he should be killed or crucified or exiled from the land; or one who commits murder for which he is killed.
Reference: Sunan Abi Dawud 4353
In-book reference: Book 40, Hadith 3
English translation: Book 39, Hadith 4339