Musannaf Ibn Abi Shayba 23:33

Hussain bin Ali narrated to us, from Za'idah, from Hisham, from al-Hasan, from Abu Musa, that the Prophet (peace be upon him) said: "There will be tribulations at the end of time like pieces of a dark night. A man will wake up as a believer and go to sleep as a disbeliever, and he will go to sleep as a believer and wake up as a disbeliever."