Musnad Ahmad 28:150

Musa ibn Dawud narrated to us, Ibn Lahi'ah narrated to us, from Huyayy ibn 'Abd Allah, from Abu 'Abd al-Rahman al-Hubuli, from 'Abd Allah ibn 'Amr: That the Messenger of Allah, peace and blessings of Allah be upon him, said: "Fasting and the Qur'an will intercede for the servant on the Day of Resurrection. Fasting will say: 'O Lord, I prevented him from food and desires during the day, so let me intercede for him.' And the Qur'an will say: 'I prevented him from sleep at night, so let me intercede for him.'" He said: "So they will intercede."