Sahih Bukhari Volume 4, Book 56, Hadith Number 816.

Narated By Jabir bin Samura : The Prophet said, “When Khosrau perishes, there will be no more Khosrau a after him, and when Caesar perishes, there will be no more Caesar after him,” The Prophet also said, “You will spend the treasures of both of them in Allah’s Cause.”