Musnad Ahmad 716:0

Nafi‘ ibn ‘Utbah ibn Abi Waqqas reported: I was with the Messenger of Allah (ﷺ) on a campaign, and he came to a people who were wearing wool. They were near a mound, and he stood by them. I stood between him and them, and I kept silent for a moment. Then he said: "You will fight the Arabian Peninsula, 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 the Romans, and Allah will grant you victory over it. Then you will fight the Dajjal, and Allah will grant you victory over him." Nafi‘ said: "O Jabir, we do not see the Dajjal appearing until the Romans are fought."