Musnad Ahmad 340:2

'Abd al-Malik ibn 'Amr narrated to us, he said: Hisham narrated to us, from Yahya ibn Abi Kathir, from Abu Salamah, who said: Rabi'ah ibn Ka'b al-Aslami narrated to me, he said: I used to spend the night at the door of the Messenger of Allah (peace and blessings of Allah be upon him), providing him with his water for ablution. I would hear him after a portion of the night had passed saying: "Allah hears those who praise Him." And I would hear him after a portion of the night had passed saying: "All praise is due to Allah, Lord of the worlds."