Sunan Abi Dawud Book 35, Hadith 38
I had a hanging lock of hair. My mother said to me: I shall not cut it, for the Messenger of Allah (ﷺ) used to stretch it our and hold it.
The Prophet (ﷺ) saw a boy with part of his head shaved and part left unshaven. He forbade them to do that, saying: Shave it all or leave it all.
Al-Hajjaj ibn Hassan said: We entered upon Anas ibn Malik. My sister al-Mughirah said: You were a boy in those days and you had two locks of hair. He (Anas) rubbed your head and invoked blessing on you. He said: Shave them (i.e. the locks) or clip them, for this is the fashion of the Jews.