Sahih al-Bukhari 6311

Musaddad narrated to us: Mutamir narrated to us, saying: I heard Mansur, from Sad ibn Ubaydah, who said: al-Bara ibn Azib, may Allah be pleased with them both, told me: The Messenger of Allah, peace and blessings be upon him, said: When you go to your bed, perform ablution as you do for prayer, then lie on your right side and say: O Allah, I surrender my face to You, entrust my affair to You, and rely upon You, in hope and fear of You. There is no refuge or escape from You except to You. I believe in Your Book which You revealed and in Your Prophet whom You sent. If you die, you will die upon the natural faith, so make these the last words you say. I said, ‘I will commit them to memory along with the words: and in Your Messenger whom You sent.’ He said, ‘No. Say: and in Your Prophet whom You sent.’