Musnad Ahmad 30:1893

Bahz narrated to us, he said: Shu'bah narrated to us, he said: Habib ibn Abi Thabit informed me, he said: I heard 'Umarah ibn 'Umayr, from Abu al-Mutawwas, from his father, from Abu Hurayrah, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever breaks his fast for one day of Ramadan without a concession that Allah has granted him, the entire lifetime will not be accepted from him."