Reference: Siyar A’laam an-Nubalaa v6 p376
al-Falaas رحمه الله said: I heard say:
Daawood ibn Abi Hind رحمه الله [voluntarily] fasted for forty years, and his family were not aware of it. He was very discrete, and would take his [packed] lunch with him, and then give it away [to someone needy] along the way.
