Hadith: When Messenger of Allah (may Allah's peace and blessings be upon him) came to Mina, he went to "Jamrat al-‘Aqabah" and threw pebbles at it. After that, he went to his tent in Mina and sacrificed. Thenو he called for a barber, pointed at the right side of his head, and said: "Shave from here." Then, he pointed at his left side and said: "Take (hair) from here." Then, he distributed his hair among the people.

عن أنس بن مالك رضي الله عنه أن رسول الله صلى الله عليه وسلم أتى مِنَى، فأتى الجَمْرَةَ فرماها، ثم أتى منزله بمِنَى ونحر، ثم قال للحلاق: «خُذْ» وأشار إلى جانبه الأيمن، ثم الأيسر، ثم جعل يعطيه الناسَ. وفي رواية: لما رمى الجَمْرَةَ، ونحر نُسُكَهُ وحلق، ناول الحلاق شِقَّهُ الأيمن فحلقه، ثم دعا أبا طلحة الأنصاري رضي الله عنه فأعطاه إياه، ثم ناوله الشِّقَّ الأَيْسَرَ، فقال: «احْلِقْ»، فحلقه فأعطاه أبا طلحة، فقال: «اقْسِمْهُ بين الناس».
[صحيح] - [رواه مسلم بروايتيه]

Anas ibn Mālik, (may Allah be pleased with him) reported that when Messenger of Allah (may Allah's peace and blessings be upon him) came to Mina, he went to "Jamrat al-‘Aqabah" and threw pebbles at it. After that, he went to his tent in Mina and sacrificed. Then, he called for a barber, pointed at the right side of his head, and said: "Shave from here." Then, he pointed at his left side and said: "Take (hair) from here." Then, he distributed his hair among the people. In another narration: "After he threw pebbles at "Jamarat al-‘Aqabah", he slaughtered his animal, then shaved his head. The barber started with the right side of his head, then he called Abu Talhah al-Ansāri and gave the hair to him. Then, he asked to shave his left side, and said: "Shave it!" The barber shaved it and he gave the hair to Abu Talhah. Then, he said: "Distribute it among the people!"
Sahih/Authentic. - [Muslim with its two versions]

Explanation

When the Prophet (may Allah's peace and blessings be upon him) arrived at Mina on the day of Eid during his Farewell Pilgrimage, he threw pebbles at "Jamarat al-‘Aqabah", and then he went to his tent and slaughtered his sacrifice. Then, he called for a barber to shave his head. He told the barber to start with the right side of his head, and he started from there. Then he called Abu Talhah al-Ansāri and gave him the hair that was shaved off his right side. Then, he shaved the remainder of his head and gave the hair to Abu Talhah, and said: "Distribute it among the people!" He did it. Some people received one hair, some two, and some more than that. This was to seek blessings in his hair. Such act is permissible but exclusive to Prophet Muhammad's belongings.