Musannaf Ibn Abi Shayba 21:174

Sufyan ibn 'Uyaynah narrated to us, from Abu Ishaq, from al-Bara', who said: When the Prophet, peace and blessings of Allah be upon him, would take to his bed, he would say: "O Allah, to You I have submitted my soul, and to You I have turned my face, and to You I have entrusted my affair, and to You I have leaned my back, 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 Prophet—or Your Messenger—whom You sent."