Rabi'a ibn Ka'b related, "I used to spend the night at the door
of the Prophet, may Allah bless him and grant him peace, and I would give
him his wudu' water." He said, "After a long period of the night had passed,
I heard him say, 'Allah hears whoever praises Him,' and I heard him say
after a long period of the night had passed, 'Praise be to Allah, Lord
of the Worlds.'"