Musannaf Ibn Abi Shayba 17:1230

Abu al-Ahwas narrated to us, from Abu Ishaq, from al-Bara’, who said: The Messenger of Allah (may Allah bless him and grant him peace) said to a man: "O so-and-so, when you go to your bed, 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. There is no refuge and no escape from You except to You. I have believed in Your Book which You revealed, and Your Prophet whom You sent.' For if you die during your night, you will die upon the natural disposition (fitra), and if you wake up, you will wake up to good."