Musannaf Ibn Abi Shaybah 1074 — Those who said: wash the hair

Sayyiduna Ali (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever, while taking the ritual bath for janabah, leaves unwashed on his body even a place the size of one hair, such and such will be done to him in the Fire." Sayyiduna Ali (may Allah be pleased with him) said: "From then on I became an enemy of my hair." Sayyiduna Ali (may Allah be pleased with him) used to shave his head.