Prayer at Night (Tahajjud)

Bukhari :: Book 2 :: Volume 21 :: Hadith 226

Narrated Um Salama:

One night the Prophet got up and said, "Subhan Allah! How many afflictions Allah has revealed tonight and how many treasures have been sent down (disclosed). Go and wake the sleeping lady occupants of these dwellings up (for prayers), perhaps a well-dressed in this world may be naked in the Hereafter."