Narrated Sa'id ibn Zayd: We were with the Prophet (ﷺ). He mentioned civil strife (fitnah) and expressed its gravity. We or the people said: Messenger of Allah, if this happens to us it will destroy us. The Messenger of Allah (ﷺ) said; No. It is enough for you that you would be killed. Sa'id said: I saw that my brethren were killed.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا أَبُو الأَحْوَصِ، سَلاَّمُ بْنُ سُلَيْمٍ عَنْ مَنْصُورٍ، عَنْ هِلاَلِ بْنِ يِسَافٍ، عَنْ سَعِيدِ بْنِ زَيْدٍ، قَالَ كُنَّا عِنْدَ النَّبِيِّ صلى الله عليه وسلم فَذَكَرَ فِتْنَةً فَعَظَّمَ أَمْرَهَا فَقُلْنَا أَوْ قَالُوا يَا رَسُولَ اللَّهِ لَئِنْ أَدْرَكَتْنَا هَذِهِ لَتُهْلِكَنَّا . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " كَلاَّ إِنَّ بِحَسْبِكُمُ الْقَتْلُ " . قَالَ سَعِيدٌ فَرَأَيْتُ إِخْوَانِي قُتِلُوا .
sunnah.com