Sahih Bukhari
Sahih Bukhari Volume 009, Book 084, Hadith Number 069.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 84. Dealing with Apostates
Narrated By Abu Huraira : Allah's Apostle said, "The Hour will not be established till two (huge) groups fight against each other, their claim being one and the same."