Musnad Ahmad 303:15

'Affan narrated to us, Hammam narrated to us, from Qatadah, from Mutarrif, from his father, that a man asked the Prophet, peace and blessings of Allah be upon him, about fasting forever. The Prophet said: "He has neither fasted nor broken his fast," or he said: "He did not fast and he did not break his fast."