Musnad Abu Ya'la al-Mawsili 152:191

Muhammad ibn Abi Bakr narrated to us, Yahya narrated to us, from Ibn ‘Ajlan, from ‘Awn ibn ‘Abd Allah, from Ibn Mas‘ud, who said: When you narrate from the Messenger of Allah (may Allah bless him and grant him peace), then think of the Messenger of Allah as being the most prepared, the most God-fearing, and the most guided.