Sahih al-Bukhari 171
Sahih al-Bukhari · Book 4: Ablutions (Wudu') · What is said regarding the water with which human hair has been washed
Narrated Anas:
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الرَّحِيمِ ، قَالَ أَخْبَرَنَا سَعِيدُ بْنُ سُلَيْمَانَ ، قَالَ حَدَّثَنَا عَبَّادٌ ، عَنِ ابْنِ عَوْنٍ ، عَنِ ابْنِ سِيرِينَ ، عَنْ أَنَسٍ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم لَمَّا حَلَقَ رَأْسَهُ كَانَ أَبُو طَلْحَةَ أَوَّلَ مَنْ أَخَذَ مِنْ شَعَرِهِ.
When Allah's Messenger (ﷺ) got his head shaved, Abu- Talha was the first to take some of his hair.