Sahih Bukhari | Volume 8 | Hadith Number 625
Narrated by Jabir bin Samura
The Prophet said, "If Caesar is ruined, there will be no Caesar after him; and if Khosrau is ruined, there will be no Khosrau, after him; and, by Him in Whose Hand my soul is, surely you will spend their treasures in Allah's Cause."