Sunan an-Nasa'i, Book 1, Hadith 127 (In-Book) ⓘ
It was narrated that Safwan bin 'Assal said: "The Prophet granted us a dispensation when traveling, allowing us not to take off our Khuffs for three days and three nights."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَاصِمٍ، عَنْ زِرٍّ، عَنْ صَفْوَانَ بْنِ عَسَّالٍ، قَالَ رَخَّصَ لَنَا النَّبِيُّ صلى الله عليه وسلم إِذَا كُنَّا مُسَافِرِينَ أَنْ لاَ نَنْزِعَ خِفَافَنَا ثَلاَثَةَ أَيَّامٍ وَلَيَالِيَهُنَّ .
also referenced under: Volume 1, Book 1, Hadith 126 (DarusSalam)