Musnad Ahmad 33:1147

'Attab ibn Ziyad narrated to us, Abdullah narrated to us, Ibn Lahi'ah narrated to us, Abu al-Zubayr narrated to me, from Jabir, from the Prophet, peace and blessings of Allah be upon him, who said: "Fasting is only a shield, with which the servant shields himself from the Fire. It is Mine, and I reward for it."