Sahih Bukhari
Sahih Bukhari Volume 009, Book 083, Hadith Number 007.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 83. Blood Money (Ad-Diyat)
Narrated By 'Abdullah bin 'Umar : The Prophet said, "After me (i.e. after my death), do not become disbelievers, by striking (cutting) the necks of one another.