Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Ibn Abbas (may Allah be pleased with them). He says that the People of the Book used to let their hair hang loose, and the polytheists used to part their hair. In matters where the Noble Prophet Muhammad (peace and blessings be upon him) was not given any command, he preferred to follow the People of the Book. The narrator says: Thus, the Prophet (peace and blessings be upon him) let the front part of his hair hang loose, and then after that, he parted his hair.