Musannaf Ibn Abi Shayba 1:371

Waki’ narrated to us, from Usamah bin Zayd, from al-Nu’man bin Kharbudh, who said: I heard Umm Sabiyah al-Juhaniyyah saying: "My hand and the hand of the Messenger of Allah, may Allah bless him and grant him peace, would often alternate in the same vessel during ablution."