Musnad Abu Ya'la al-Mawsili 106:15

Muhammad ibn Bashar narrated to us, Abd al-Rahman and Abu Dawud narrated to us, they said: Shu'bah narrated to us, from 'Amr ibn Murrah, he said: I heard Sa'd ibn 'Ubaydah narrating from al-Bara', that the Messenger of Allah (may Allah bless him and grant him peace) commanded a man, when he took to his bed, to say: "O Allah, I have submitted my soul to You, and I have turned my face toward You, and I have entrusted my back to You, and I have committed my affair to You, out of desire and fear of You. There is no refuge and no escape from You except to You. I have believed in Your Book which You revealed, and in Your Messenger whom You sent." If he dies, he dies upon the natural disposition (fitrah).