Musnad Ahmad 788:220

Muhammad ibn Ubayd narrated to us, he said: Burayd ibn Abdullah ibn Abi Burdah narrated to us, from his father, from Abu Musa, who said: A petitioner came to the Prophet, may Allah bless him and grant him peace, and the Messenger of Allah, may Allah bless him and grant him peace, said: "Intercede, and you will be rewarded, and may Allah decree upon the tongue of His Prophet what He wills."