Musnad Ahmad 1540

It was narrated that Nafiʼ bin "Utbah bin Abi Waqqas said. The Messenger of Allah (ﷺ) said: "You will fight in Arabia and Allah will grant you victory over it, then you will fight Persia and Allah will grant you victory over it, then you will fight Byzantium and Allah will grant you victory over it. Then you will fight the Dajjal and Allah will grant you victory over him." Jabir said: The Dajjal will not emerge until the Byzantines are conquered.