Sunan Abi Dawud Book 35, Hadith 29
The hair of the Messenger of Allah (ﷺ) were above wafrah and below jummah.
The hair of Messenger of Allah (ﷺ) were halfway down his ears.
The people of the Book used to let their hair hand down, and the polytheists used to part their hair. The Messenger of Allah (ﷺ) like to confirm with the People of the Book in the matters about which he had received no command. Hence he Messenger of Allah (ﷺ) let his forelock hang down but afterwards he parted it.