From Sahih Muslim (Hadith 3154):
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 Holy 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
Reference: Muslim 3154