It is narrated from Sayyidah Aishah (may Allah be pleased with her) that when the Messenger of Allah (peace and blessings be upon him) took the ritual bath for janabah (major impurity), he (peace and blessings be upon him) would wash his hands before putting his hand into the vessel, and then perform ablution as for prayer.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 812