Narrated Abu Al-Ash'ath As-Sana'ani: "Some people were delivering Khutbah in Ash-Sham, and among them were Companions of the Prophet (ﷺ). So the last of them, a man called Murrah bin Ka'b, stood, and he said: 'If it were not for a Hadith I heard from the Messenger of Allah (ﷺ), I would not have stood (to address you). He (ﷺ) mentioned the tribulations, and that they would be coming soon. Then a man who was concealed by a garment passed by. So he said: "This one will be upon guidance that day." So I went towards him, and it was 'Uthman bin 'Affan. I turned, facing him, and I said: "This one?" He said: "Yes."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا عَبْدُ الْوَهَّابِ الثَّقَفِيُّ، قَالَ حَدَّثَنَا أَيُّوبُ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَبِي الأَشْعَثِ الصَّنْعَانِيِّ، أَنَّ خُطَبَاءَ، قَامَتْ بِالشَّامِ وَفِيهِمْ رِجَالٌ مِنْ أَصْحَابِ رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَامَ آخِرُهُمْ رَجُلٌ يُقَالُ لَهُ مُرَّةُ بْنُ كَعْبٍ فَقَالَ لَوْلاَ حَدِيثٌ سَمِعْتُهُ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم مَا قُمْتُ . وَذَكَرَ الْفِتَنَ فَقَرَّبَهَا فَمَرَّ رَجُلٌ مُقَنَّعٌ فِي ثَوْبٍ فَقَالَ هَذَا يَوْمَئِذٍ عَلَى الْهُدَى فَقُمْتُ إِلَيْهِ فَإِذَا هُوَ عُثْمَانُ بْنُ عَفَّانَ . قَالَ فَأَقْبَلْتُ عَلَيْهِ بِوَجْهِهِ فَقُلْتُ هَذَا قَالَ نَعَمْ .هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ . وَفِي الْبَابِ عَنِ ابْنِ عُمَرَ وَعَبْدِ اللَّهِ بْنِ حَوَالَةَ وَكَعْبِ بْنِ عُجْرَةَ .
sunnah.com