Sunan an-Nasa'i Book 48, Hadith 26
"When he came to the Prophet said to him: 'Come closer to me.' So he came closer to him, and he put his hand on his braid and wiped his head and prayed for him."
"Ibn Mas'ud addressed us and said: 'How do you want me to recite? According to the recitation of Zaid bin Thabit, when I learned seventy-odd Surahs from the mouth of the Messenger of Allah while Zaid was with the other boys with two braids?'"
"I came to the Prophet and I had long hair. He said: 'It is not good,' and I thought he meant me, so I went and cut my hair. He said: 'I did not mean you, but this is better.'"