Sunan an-Nasa'i Book 48, Hadith 12
"The Messenger of Allah forbade Al-Qaza' (to shave part of the head and leave part)."
The Prophet said: "Allah, the Mighty and Sublime, has forbidden me from Al-Qaza' (to shave part of the head and leave part)."
"I came to the Prophet and I had hair. He said: 'This is bad,' and I thought he meant me, so I cut my hair then I came to him. He said to me: 'I didn't mean you, but this is better.'"