Hadithcore
Sahih al-Bukhari, 388
sahih

Narrated Al-Mughira bin Shu'ba:

I helped the Prophet (ﷺ) in performing ablution and he passed his wet hands over his Khuffs and prayed.

حَدَّثَنَا إِسْحَاقُ بْنُ نَصْرٍ، قَالَ حَدَّثَنَا أَبُو أُسَامَةَ، عَنِ الأَعْمَشِ، عَنْ مُسْلِمٍ، عَنْ مَسْرُوقٍ، عَنِ الْمُغِيرَةِ بْنِ شُعْبَةَ، قَالَ وَضَّأْتُ النَّبِيَّ صلى الله عليه وسلم فَمَسَحَ عَلَى خُفَّيْهِ وَصَلَّى‏.‏

References2 variants
In-Book Reference
Book 8, Hadith 40
USC-MSA web (English) reference
Vol. 1, Book 8, Hadith 385 (deprecated numbering scheme)