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.'"