It was narrated from Jabir bin Samurah, that Nafi' bin 'Utbah bin Abu Waqqas narrated that the Prophet ﷺ said:
"You will fight the Arabian Peninsula and victory will be granted by Allah. Then you will fight the Romans and victory will be granted (by Allah). Then you will fight Dajjal and victory will be granted (by Allah)." Jabir said: "Dajjal will not appear until you have fought the Romans."

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا الْحُسَيْنُ بْنُ عَلِيٍّ، عَنْ زَائِدَةَ، عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، عَنْ نَافِعِ بْنِ عُتْبَةَ بْنِ أَبِي وَقَّاصٍ، عَنِ النَّبِيِّ ـ ﷺ ـ قَالَ " سَتُقَاتِلُونَ جَزِيرَةَ الْعَرَبِ فَيَفْتَحُهَا اللَّهُ ثُمَّ تُقَاتِلُونَ الرُّومَ فَيَفْتَحُهَا اللَّهُ ثُمَّ تُقَاتِلُونَ الدَّجَّالَ فَيَفْتَحُهَا اللَّهُ " . قَالَ جَابِرٌ فَمَا يَخْرُجُ الدَّجَّالُ حَتَّى تُفْتَحَ الرُّومُ .