Sayyiduna Jubayr bin Mut'im (may Allah be pleased with him) says: We mentioned the ritual bath for janabah (major impurity) in the presence of the Messenger of Allah (peace and blessings be upon him), and the Messenger of Allah (peace and blessings be upon him) said: "As for me, I pour water over my head three times."
(b) Zuhayr described the position of the hands: the palms facing the sky and the backs facing the ground (when scooping water).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 835