Musnad Ahmad 788:100

Waki’ narrated to us, Buraid ibn Abi Burdah ibn Abi Musa narrated to us, from his father, from his grandfather, who said: We were sitting with the Prophet, may Allah bless him and grant him peace, and a questioner asked him. The Messenger of Allah, may Allah bless him and grant him peace, said: "Intercede, and you will be rewarded, and may Allah, the Almighty and Majestic, decree upon the tongue of His Prophet what He wills."