ENOfficial
An-Nu'man b. Bashir said: I heard God's messenger say, "I have warned you of hell, I have warned you of hell," and he kept on saying it so loudly that if he had been where I am just now the people in the street would be able to hear it. He went on till a cloak he was wearing fell down at his feet. Darimi transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنِ النُّعْمَانِ بْنِ بَشِيرٍ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «أَنْذَرْتُكُمُ النَّارَ أَنْذَرْتُكُمُ النَّارَ» فَمَا زَالَ يَقُولُهَا حَتَّى لَوْ كَانَ فِي مَقَامِي هَذَا سَمِعَهُ أَهْلُ السُّوقِ وَحَتَّى سَقَطَتْ خَمِيصَةٌ كَانَتْ عَلَيْهِ عِنْدَ رجلَيْهِ. رَوَاهُ الدَّارمِيّ
sunnah.com