The fighting against Ar-Rum (the Byzantines)
حَدَّثَنِي إِسْحَاقُ بْنُ يَزِيدَ الدِّمَشْقِيُّ، حَدَّثَنَا يَحْيَى بْنُ حَمْزَةَ، قَالَ حَدَّثَنِي ثَوْرُ بْنُ يَزِيدَ، عَنْ خَالِدِ بْنِ مَعْدَانَ، أَنَّ عُمَيْرَ بْنَ الأَسْوَدِ الْعَنْسِيَّ، حَدَّثَهُ أَنَّهُ، أَتَى عُبَادَةَ بْنَ الصَّامِتِ وَهْوَ نَازِلٌ فِي سَاحِلِ حِمْصَ، وَهْوَ فِي بِنَاءٍ لَهُ وَمَعَهُ أُمُّ حَرَامٍ، قَالَ عُمَيْرٌ فَحَدَّثَتْنَا أُمُّ حَرَامٍ أَنَّهَا سَمِعَتِ النَّبِيَّ صلى الله عليه وسلم يَقُولُ " أَوَّلُ جَيْشٍ مِنْ أُمَّتِي يَغْزُونَ الْبَحْرَ قَدْ أَوْجَبُوا ". قَالَتْ أُمُّ حَرَامٍ قُلْتُ يَا رَسُولَ اللَّهِ أَنَا فِيهِمْ. قَالَ " أَنْتِ فِيهِمْ ". ثُمَّ قَالَ النَّبِيُّ صلى الله عليه وسلم " أَوَّلُ جَيْشٍ مِنْ أُمَّتِي يَغْزُونَ مَدِينَةَ قَيْصَرَ مَغْفُورٌ لَهُمْ ". فَقُلْتُ أَنَا فِيهِمْ يَا رَسُولَ اللَّهِ. قَالَ " لاَ ".
Narrated Khalid bin Madan: That 'Umair bin Al-Aswad Al-Anasi told him that he went to 'Ubada bin As-Samit while he was staying in his house at the sea-shore of Hims with (his wife) Um Haram. 'Umair said. Um Haram informed us that she heard the Prophet (ﷺ) saying, "Paradise is granted to the first batch of my followers who will undertake a naval expedition." Um Haram added, I said, 'O Allah's Messenger! Will I be amongst them?' He replied, 'You are amongst them.' The Prophet (ﷺ) then said, 'The first army amongst' my followers who will invade Caesar's City will be forgiven their sins.' I asked, 'Will I be one of them, O Allah's Messenger?' He replied in the negative."