Sahih al-Bukhari 206
Narrated `Urwa bin Al-Mughira:
My father said, "Once I was in the company of the Prophet (ﷺ) on a journey and I dashed to take off his 
Khuffs (socks made from thick fabric or leather). He ordered me to leave them as he had put them 
after performing ablution. So he passed wet hands over them.
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا زَكَرِيَّاءُ، عَنْ عَامِرٍ، عَنْ عُرْوَةَ بْنِ الْمُغِيرَةِ، عَنْ أَبِيهِ، قَالَ كُنْتُ مَعَ النَّبِيِّ صلى الله عليه وسلم فِي سَفَرٍ، فَأَهْوَيْتُ لأَنْزِعَ خُفَّيْهِ فَقَالَ ‏
"‏ دَعْهُمَا، فَإِنِّي أَدْخَلْتُهُمَا طَاهِرَتَيْنِ ‏"‏‏.‏ فَمَسَحَ عَلَيْهِمَا‏.‏