Musnad Ahmad 422:2

'Abdullah ibn Ahmad said: 'Uthman ibn Muhammad ibn Abi Shaybah narrated to me, he said: Sa'id ibn Khuthaym al-Hilali narrated to us, he said: I heard my grandmother, Rabi'ah bint 'Iyad, from her grandfather, 'Ubaydah ibn 'Amr al-Kilabi, who said: I saw the Messenger of Allah, peace and blessings of Allah be upon him, perform ablution, and he perfected the ablution. He said: And Rabi'ah, when she performed ablution, would perfect the ablution.