Musannaf Ibn Abi Shayba 1:112

Zayd ibn al-Hubab narrated to us, from Umar ibn Sulaym al-Bahili, who said: Abu Ghalib narrated to me. He said: I said to Abu Umamah, "Inform us about the ablution (wudu) of the Messenger of Allah, may Allah bless him and grant him peace." So he performed ablution three times [for each part] and combed his beard with his fingers. And he said, "Thus I saw the Messenger of Allah, may Allah bless him and grant him peace, doing."