When the Messenger of Allah ﷺ stood up for prayer, he would say the takbir, then he would say, "I have turned my face toward the One who created the heavens and the earth, as a sincere monotheist" [Anam 6:79], submitting, and I am not among those who associate partners with Allah. "Indeed my prayer, my rites, my life, and my death are for Allah, Lord of all the worlds. He has no partner. With this I have been commanded, and I am the first of those who submit" [Anam 6:162–163].O Allah, You are the King. There is no god for me but You. You are my Lord and I am Your servant. I have wronged myself and I confess my sin, so forgive me all my sins, for none forgives sins but You. Guide me to the best of character, for none guides to the best of it but You, and turn away from me its worst, for none turns away its worst but You. Here I am at Your service, and all good is in Your hands, while evil is not attributed to You. I exist through You and return to You. Blessed and exalted are You. I seek Your forgiveness and turn to You in repentance.When he bowed, he would say, "O Allah, to You I have bowed, in You I have believed, and to You I have submitted. My hearing, my sight, my mind, my bones, and my sinews are humbled before You."When he raised his head, he would say, "Allah hears whoever praises Him. Our Lord, to You belongs all praise, filling the heavens and the earth, filling what is between them, and filling whatever else You will."When he prostrated, he would say, "O Allah, to You I have prostrated, in You I have believed, and to You I have submitted. My face has prostrated to the One who created it and shaped it, fashioning it beautifully, and who opened its hearing and its sight. Blessed is Allah, the best of creators."When he said the salam at the end of the prayer, he would say, "O Allah, forgive me what I have done before and what I will do later, what I have concealed and what I have done openly, what I have committed in excess, and what You know better than I. You are the One who brings forward and the One who delays. There is no god but You."
حدثنا عبيد الله بن معاذ حدثنا أبي حدثنا عبد العزيز بن أبي سلمة عن عمه الماجشون بن أبي سلمة عن عبد الرحمن الأعرج عن عبيد الله بن أبي رافع
كان رسول الله ﷺ إذا قام إلى الصلاة كبر ثم قال {وجهت وجهي للذي فطر السموات والأرض حنيفا} مسلما وما أنا من المشركين {إن صلاتي ونسكي ومحياي ومماتي لله رب العالمين لا شريك له وبذلك أمرت وأنا أول المسلمين} اللهم أنت الملك لا إله لي إلا أنت أنت ربي وأنا عبدك ظلمت نفسي واعترفت بذنبي فاغفر لي ذنوبي جميعا إنه لا يغفر الذنوب إلا أنت واهدني لأحسن الأخلاق لا يهدي لأحسنها إلا أنت واصرف عني سيئها لا يصرف سيئها إلا أنت لبيك وسعديك والخير كله في يديك والشر ليس إليك أنا بك وإليك تباركت وتعاليت أستغفرك وأتوب إليك وإذا ركع قال اللهم لك ركعت وبك آمنت ولك أسلمت خشع لك سمعي وبصري ومخي وعظامي وعصبي وإذا رفع قال سمع الله لمن حمده ربنا ولك الحمد ملء السموات والأرض وملء ما بينهما وملء ما شئت من شيء بعد وإذا سجد قال اللهم لك سجدت وبك آمنت ولك أسلمت سجد وجهي للذي خلقه وصوره فأحسن صورته وشق سمعه وبصره وتبارك الله أحسن الخالقين وإذا سلم من الصلاة قال اللهم اغفر لي ما قدمت وما أخرت وما أسررت وما أعلنت وما أسرفت وما أنت أعلم به مني أنت المقدم والمؤخر لا إله إلا أنت
Muslim narrated it in Kitab al-Salah, Chapter on the prayer of the Prophet ﷺ and his supplication at night, hadith no. 771, from the hadith of Abdul-Aziz bin Abu Salama, with this wording.