Musnad Ahmad 1153:1803

Isma'il narrated to us, from Khalid, who said: A man narrated to me, from Abu al-'Aliyah, from 'Aishah, that the Prophet, peace and blessings of Allah be upon him, used to say during the prostration of the Qur'an at night—he would say it repeatedly in the prostration: "My face has prostrated to the One who created it, and fashioned its hearing and its sight by His might and His power."