The Messenger of Allah ﷺ said, "When Khosrow perishes, there will be no Khosrow after him, and when Caesar perishes, there will be no Caesar after him. By the One in whose hand is the soul of Muhammad, their treasures will surely be spent in the cause of Allah."
قال رسول الله ﷺ: إذا هلك كسرى فلا كسرى بعده، وإذا هلك قيصر فلا قيصر بعده، والذي نفس محمد بيده لتنفقن كنوزهما في سبيل الله.
Bukhari narrated it in "The Obligation of Khumus" (3121), and Muslim narrated it in "Tribulations" (2919:77), both through Jareer, from Abdul-Malik bin Umayr, from Jabir bin Samura, who narrated it.