Yahya related to me from Malik from Zayd ibn Aslam that Ata ibnYasar told him that the Messenger of Allah, may Allah bless him andgrant him peace, was in the mosque when a man came in with dishevelledhair and beard. The Messenger of Allah. may Allah bless him and granthim peace, motioned with his hand that he should be sent out to groomhis hair and beard. The man did so and then returned. The Messenger ofAllah, may Allah bless him and grant him peace, said, "Isn't thisbetter than that one of you should come with his head dishevelled, asif he were a shaytan?"
USC-MSA web (English) reference: Book 51, Hadith 7
Arabic reference: Book 51, Hadith 1739