Abu Dawud Book 28, Hadith Number 4178.
Chapter : Growing long hair.
Narated By Wa’il ibn Hujr : I came to the Prophet (PBUH) and I had long hair. When the Apostle of Allah (PBUH) 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.