Mukhtasar Muslim

Abu Huraira (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: When Kisra (the king of Persia) dies, there will be no Kisra after him, and when Caesar (the king of Rome) dies, there will be no Caesar after him (and these two lands will be conquered by the Muslims). By Him in Whose hand is my soul, the treasures of both of them will be spent in the way of Allah.