Musannaf Ibn Abi Shaybah 26702 — Keeping long locks and hair

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that he said: The People of the Book used to let their hair hang down (sadl), and the polytheists used to part the hair on their heads. In matters about which the Prophet (peace and blessings be upon him) had been given no command, he (peace and blessings be upon him) liked to conform to the People of the Book. The narrator said: So he (peace and blessings be upon him) let the hair at the front of his head hang down, that is, left it loose, and afterwards he (peace and blessings be upon him) parted it.