Musnad Abu Ya'la al-Mawsili 7:19

Muhammad ibn Abi Bakr al-Muqaddami narrated to us, Yusuf ibn Yazid narrated to us, Ibrahim ibn Umar ibn Aban narrated to us, from Ibn Shihab, from his father, from Abd al-Rahman ibn Awf, that he witnessed that when Uthman ibn Affan gave the Messenger of Allah (may Allah bless him and grant him peace) what he equipped the Army of Hardship with. And he brought seven hundred uqiyah of gold.