ENOfficial
It was narrated from Salamah bin Nubait that his father said: "I saw the Messenger of Allah (ﷺ) delivering a Khutbah on the day of Arafat atop a red camel."
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا مُحَمَّدُ بْنُ آدَمَ، عَنِ ابْنِ الْمُبَارَكِ، عَنْ سَلَمَةَ بْنِ نُبَيْطٍ، عَنْ أَبِيهِ، قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَخْطُبُ يَوْمَ عَرَفَةَ عَلَى جَمَلٍ أَحْمَرَ .
sunnah.com