Musnad Ahmad 788:227

Waki’ narrated to us, he said: Shu’bah narrated to us, from Qatadah, from Abu Tamimah, from Abu Musa. Waki’ said: And al-Dahhak Abu al-‘Ala’ narrated to me that he heard it from Abu Tamimah, from Abu Musa, from the Prophet, peace and blessings of Allah be upon him, who said: "Whoever fasts forever, Hell will be narrowed upon him like this." And he clenched his fist.