Hadithcore
Sahih Muslim, 1305 c
sahih

Anas b. Malik (Allah be pleased with him) reported that Allah's Messenger (ﷺ) threw stones at Jamrat al-'Aqaba. He then want to his sacrificial animal and sacrificed it, and there was sitting the barber, and he pointed with his hand towards his head, and he shaved the right half of it, and he (the Prophet) distributed them (the hair) among those who were near him. And he again said:

Shave the other half, and said: Where is Abu Talha and gave it (the hair) to him.

وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الأَعْلَى، حَدَّثَنَا هِشَامٌ، عَنْ مُحَمَّدٍ، عَنْ أَنَسِ، بْنِ مَالِكٍ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَمَى جَمْرَةَ الْعَقَبَةِ ثُمَّ انْصَرَفَ إِلَى الْبُدْنِ فَنَحَرَهَا وَالْحَجَّامُ جَالِسٌ وَقَالَ بِيَدِهِ عَنْ رَأْسِهِ فَحَلَقَ شِقَّهُ الأَيْمَنَ فَقَسَمَهُ فِيمَنْ يَلِيهِ ثُمَّ قَالَ ‏"‏ احْلِقِ الشِّقَّ الآخَرَ ‏"‏ ‏.‏ فَقَالَ ‏"‏ أَيْنَ أَبُو طَلْحَةَ ‏"‏ ‏.‏ فَأَعْطَاهُ إِيَّاهُ ‏.‏

References2 variants
In-Book Reference
Book 15, Hadith 358
USC-MSA web (English) reference
Book 7, Hadith 2993 (deprecated numbering scheme)