Sahih al-Bukhari, Book 28, Hadith 23 (In-Book) ⓘ
Narrated Ibn `Abbas: The Prophet delivered a sermon at `Arafat and said, "Whoever does not get an Izar can wear trousers, and whoever cannot get a pair of shoes can wear Khuffs (socks made from thick fabric or leather)."
حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، حَدَّثَنَا عَمْرُو بْنُ دِينَارٍ، عَنْ جَابِرِ بْنِ زَيْدٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ خَطَبَنَا النَّبِيُّ صلى الله عليه وسلم بِعَرَفَاتٍ فَقَالَ " مَنْ لَمْ يَجِدِ الإِزَارَ فَلْيَلْبَسِ السَّرَاوِيلَ، وَمَنْ لَمْ يَجِدِ النَّعْلَيْنِ فَلْيَلْبَسِ الْخُفَّيْنِ " .
also referenced under: Hadith 1843 (DarusSalam) & Volume 3, Book 29, Hadith 69 (USC-MSA)