It is narrated from Sayyidah Rubayyi' bint Mu'awwidh (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) performed ablution in her presence, and he wiped his head. He wiped the whole head over the hair, every part in the direction in which the hair grows, and he did not move the hair from its position.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 275
(a) It is narrated from Sayyiduna Anas (may Allah be pleased with him) that when he wiped his head, he would not turn his hair over.
(b) Abu Abdullah (Imam Ahmad, may Allah have mercy on him) said: This report and the report of Sayyidah Rubayyi' (may Allah be pleased with her) have one and the same meaning: he would not turn the hair over from its place.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 276