Abu Sa'id al-Khudri, may Allah be pleased with him, narrates: The Messenger of Allah, peace and blessings be upon him, said: "If a person performs any deed inside a rock that has neither a door nor a window, then whatever that deed may be, it becomes manifest to the people." Its chain is Hasan. Narrated by al-Bayhaqi in Shu'ab al-Iman.