Sunan an-Nasa'i Book 48, Hadith 27
"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.'"
"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."
"The Messenger of Allah said: 'O Ruwaifi', you may live for a long time after me, so tell the people that whoever ties up his beard, or twists it, or hangs an amulet, or cleans himself (after relieving himself) with animal dung or bones, Muhammad has nothing to do with him.'"