كتاب الفتن وأشراط الساعة
54  
The Book of Tribulations and Portents of the Last Hour
(10)
Chapter: The Hour Will Begin When The Byzantines Are The Most Prevalent Of People
(10)
باب تَقُومُ السَّاعَةُ وَالرُّومُ أَكْثَرُ النَّاسِ
Sahih Muslim 2898 a

Mustaurid al-Qurashi reported:

I heard Allah's Messenger (ﷺ) as saying: The Last Hour would come (when) the Romans would form a majority amongst people. 'Amr said to him (Mustaurid Qurashi): See what you are saying? He said: I say what I heard from Allah's Messenger (ﷺ). Thereupon he said: If you say that, it is a fact for they have four qualities. They have the patience to undergo a trial and immediately restore themselves to sanity after trouble and attack again after flight. They (have the quality) of being good to the destitute and the orphans, to the weak and, fifthly, the good quality in them is that they put resistance against the oppression of kings.
حَدَّثَنَا عَبْدُ الْمَلِكِ بْنُ شُعَيْبِ بْنِ اللَّيْثِ، حَدَّثَنِي عَبْدُ اللَّهِ بْنُ وَهْبٍ، أَخْبَرَنِي اللَّيْثُ، بْنُ سَعْدٍ حَدَّثَنِي مُوسَى بْنُ عُلَىٍّ، عَنْ أَبِيهِ، قَالَ قَالَ الْمُسْتَوْرِدُ الْقُرَشِيُّ عِنْدَ عَمْرِو بْنِ الْعَاصِ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ تَقُومُ السَّاعَةُ وَالرُّومُ أَكْثَرُ النَّاسِ ‏"‏ ‏.‏ فَقَالَ لَهُ عَمْرٌو أَبْصِرْ مَا تَقُولُ ‏.‏ قَالَ أَقُولُ مَا سَمِعْتُ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ لَئِنْ قُلْتَ ذَلِكَ إِنَّ فِيهِمْ لَخِصَالاً أَرْبَعًا إِنَّهُمْ لأَحْلَمُ النَّاسِ عِنْدَ فِتْنَةٍ وَأَسْرَعُهُمْ إِفَاقَةً بَعْدَ مُصِيبَةٍ وَأَوْشَكُهُمْ كَرَّةً بَعْدَ فَرَّةٍ وَخَيْرُهُمْ لِمِسْكِينٍ وَيَتِيمٍ وَضَعِيفٍ وَخَامِسَةٌ حَسَنَةٌ جَمِيلَةٌ وَأَمْنَعُهُمْ مِنْ ظُلْمِ الْمُلُوكِ ‏.‏
Reference : Sahih Muslim 2898a
In-book reference : Book 54, Hadith 45
USC-MSA web (English) reference : Book 41, Hadith 6925
  (deprecated numbering scheme)