Musnad Ahmad 10:15

'Affan narrated to us, Hammad ibn Salamah narrated to us, Hisham ibn 'Urwah narrated to us, from 'Urwah, that 'Abd al-Rahman ibn 'Awf said: "The Messenger of Allah, peace and blessings of Allah be upon him, granted me and 'Umar ibn al-Khattab land such-and-such." Al-Zubayr went to the family of 'Umar and bought their share from them. Then he came to 'Uthman ibn 'Affan and said: "'Abd al-Rahman ibn 'Awf claims that the Messenger of Allah, peace and blessings of Allah be upon him, granted him and 'Umar ibn al-Khattab land such-and-such, and I have bought the share of the family of 'Umar." 'Uthman said: "'Abd al-Rahman's testimony is valid for him and against him."