Sahih al-Bukhari 7424

Ibrahim at-Tami related from his father that Abu Dharr said, "I entered the mosque while the Messenger of Allah, may Allah bless him and grant him peace, was seated, When the sun set, he said, 'Abu Dharr, do you know where this goes?' I answered, 'Allah and his mother knows best.' He said, 'It goes to ask permission for prostration, and it is given permission. It will be as if it is told, 'Go back from whence you came,' and it will rise from the west.' Then he recited 'That is a period determined for it' (36:38)" in the reading of 'Abdullah [ibn Mas'ud].* [* instead of "runs its course for a period determined for it".]