Musnad Ahmad 28:121

Hassan narrated to us, Ibn Lahi'ah narrated to us, Huyayy ibn Abdullah narrated to us, that Abu Abd al-Rahman al-Hubuli narrated to him, saying: Abdullah ibn Amr brought out a parchment for us and said: The Messenger of Allah, peace and blessings of Allah be upon him, used to teach us, saying: "O Allah, Originator of the heavens and the earth, Knower of the unseen and the witnessed, You are the Lord of everything and the God of everything. I bear witness that there is no god but You, alone, with no partner, and that Muhammad is Your servant and Your Messenger, and the angels bear witness. I seek refuge in You from Satan and his shirk (polytheism/associating partners with Allah), and I seek refuge in You from committing a sin against myself or dragging it upon a Muslim." Abu Abd al-Rahman said: "The Messenger of Allah, peace and blessings of Allah be upon him, used to teach Abdullah ibn Amr to say that when he wanted to sleep."