It is narrated from Ali (may Allah be pleased with him) that when the Prophet (ﷺ) would bow (in rukū‘), he would recite: "O Allah! I have bowed for You, and I have believed in You, and I have submitted to You, and You alone are my Lord. My ears, my eyes, my mind, my bones, and my body—whatever my feet have carried—have humbled themselves for You, for Allah, the Lord of all the worlds."
Hadith Referenceمسند الإمام الشافعي / كتاب الصلاة / 227
Hadith Takhrijأخرجہ مسلم، الصلوة، باب صلاة النبي ﷺ ودعائه باللیل : (771)