Whenever the Prophet ﷺ bowed in prayer, he would say, "O Allah, to You I have bowed, in You I have believed, to You I have submitted. My hearing, my sight, my mind, my bones, and my sinews are humbled before You."And when he prostrated, he would say, "O Allah, to You I have prostrated, in You I have believed, to You I have submitted. My face has prostrated to the One who created it, shaped it, and gave it hearing and sight. Blessed is Allah, the best of creators."
كان النبي ﷺ يقول إذا ركع: اللهم لك ركعت، وبك آمنت، ولك أسلمت، خشع لك سمعي، وبصري، ومخي وعظمي وعصبي. وإذا سجد يقول: اللهم لك سجدت، وبك آمنت، ولك أسلمت، سجد وجهي للذي خلقه، وصوره، وشق سمعه، وبصره، تبارك الله أحسن الخالقين.
Muslim reported it in the chapter on the prayer of the traveler (771). See the chapter on what has been mentioned regarding the supplication of the Prophet ﷺ during the two pauses after the takbir.