(1) باب الْحُكْمِ فِيمَنِ ارْتَدَّ
`Abd Allah (b. Mas`ud) reported the Messenger of Allah (peace be upon him) as saying:
The blood of a Muslim man who testifies that there is no god but Allah and that I am the Messenger of Allah should not be lawfully shed but only for one of three reasons: married fornicator, soul for soul, and one who deserts his religion separating himself from the community.
Reference: Sunan Abi Dawud 4352
In-book reference: Book 40, Hadith 2
English translation: Book 39, Hadith 4338