Combing the Hair (Kitab Al-Tarajjul)
Dawud :: Book 33 : Hadith 4178
Narrated Wa'il ibn Hujr:
I came to the Prophet (peace_be_upon_him) and I had long hair. When the Apostle of Allah (peace_be_upon_him) saw me, he said: Evil, evil! He said: I then returned and cut them off. I then came to him in the morning. He said (to me): I did not intend to do evil to you. This is much better.