'Ali b. Abu Talib reported that when the Messenger of Allah (ﷺ) got up at night for prayer he would say:

I turn my face in complete devotion to One Who is the Originator of the heaven and the earth and I am not of the polytheists. Verily my prayer, my sacrifice, my living and my dying are for Allah, the Lord of the worlds; There is no partner with Him and this is what I have been commanded (to profess and believe) and I am of the believers. O Allah, Thou art the King, there is no god but Thee, Thou art my Lord, and I am Thy bondman. I wronged myself and make a confession of my Sin. Forgive all my sins, for no one forgives the sins but Thee, and guide me in the best of conduct for none but Thee guideth anyone (in) good conduct. Remove sins from me, for none else but Thou can remove sins from me. Here I am at Thy service, and Grace is to Thee and the whole of good is in Thine hand, and one cannot get nearneststo Thee through evil. My (power as well as existence) is due to Thee (Thine grace) and I turn to Thee (for supplication). Thou art blessed and Thou art exalted. I seek forgiveness from Thee and turn to Thee in repentance: and when he would bow, he would say: O Allah, it is for Thee that I bowed. I affirm my faith in Thee and I submit to Thee, and submit humbly before Thee my hearing, my eyesight, my marrow, my bone, my sinew; and when he would raise his head, he would say: O Allah, our Lord, praise is due to Thee, (the praise) with which is filled the heavens and the earth, and with which is filled that (space) which exists between them, and filled with anything that Thou desireth afterward. And when he prostrated himself, he (the Holy Prophet) would say: O Allah, it is to Thee that I prostrate myself and it is in Thee that I affirm my faith, and I submit to Thee. My face is submitted before One Who created it, and shaped it, and opened his faculties of hearing and seeing. Blessed is Allah, the best of Creators; and he would then say between Tashahhud and the pronouncing of salutation: Forgive me of the earlier and later open and secret (sins) and that where I made transgression and that Thou knowest better than I. Thou art the First and the Last. There is no god, but Thee.
حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي بَكْرٍ الْمُقَدَّمِيُّ، حَدَّثَنَا يُوسُفُ الْمَاجِشُونُ، حَدَّثَنِي أَبِي، عَنْ عَبْدِ، الرَّحْمَنِ الأَعْرَجِ عَنْ عُبَيْدِ اللَّهِ بْنِ أَبِي رَافِعٍ، عَنْ عَلِيِّ بْنِ أَبِي طَالِبٍ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ كَانَ إِذَا قَامَ إِلَى الصَّلاَةِ قَالَ ‏"‏ وَجَّهْتُ وَجْهِيَ لِلَّذِي فَطَرَ السَّمَوَاتِ وَالأَرْضَ حَنِيفًا وَمَا أَنَا مِنَ الْمُشْرِكِينَ إِنَّ صَلاَتِي وَنُسُكِي وَمَحْيَاىَ وَمَمَاتِي لِلَّهِ رَبِّ الْعَالَمِينَ لاَ شَرِيكَ لَهُ وَبِذَلِكَ أُمِرْتُ وَأَنَا مِنَ الْمُسْلِمِينَ اللَّهُمَّ أَنْتَ الْمَلِكُ لاَ إِلَهَ إِلاَّ أَنْتَ ‏.‏ أَنْتَ رَبِّي وَأَنَا عَبْدُكَ ظَلَمْتُ نَفْسِي وَاعْتَرَفْتُ بِذَنْبِي فَاغْفِرْ لِي ذُنُوبِي جَمِيعًا إِنَّهُ لاَ يَغْفِرُ الذُّنُوبَ إِلاَّ أَنْتَ وَاهْدِنِي لأَحْسَنِ الأَخْلاَقِ لاَ يَهْدِي لأَحْسَنِهَا إِلاَّ أَنْتَ وَاصْرِفْ عَنِّي سَيِّئَهَا لاَ يَصْرِفُ عَنِّي سَيِّئَهَا إِلاَّ أَنْتَ لَبَّيْكَ وَسَعْدَيْكَ وَالْخَيْرُ كُلُّهُ فِي يَدَيْكَ وَالشَّرُّ لَيْسَ إِلَيْكَ أَنَا بِكَ وَإِلَيْكَ تَبَارَكْتَ وَتَعَالَيْتَ أَسْتَغْفِرُكَ وَأَتُوبُ إِلَيْكَ ‏"‏ ‏.‏ وَإِذَا رَكَعَ قَالَ ‏"‏ اللَّهُمَّ لَكَ رَكَعْتُ وَبِكَ آمَنْتُ وَلَكَ أَسْلَمْتُ خَشَعَ لَكَ سَمْعِي وَبَصَرِي وَمُخِّي وَعَظْمِي وَعَصَبِي ‏"‏ ‏.‏ وَإِذَا رَفَعَ قَالَ ‏"‏ اللَّهُمَّ رَبَّنَا لَكَ الْحَمْدُ مِلْءَ السَّمَوَاتِ وَمِلْءَ الأَرْضِ وَمِلْءَ مَا بَيْنَهُمَا وَمِلْءَ مَا شِئْتَ مِنْ شَىْءٍ بَعْدُ ‏"‏ ‏.‏ وَإِذَا سَجَدَ قَالَ ‏"‏ اللَّهُمَّ لَكَ سَجَدْتُ وَبِكَ آمَنْتُ وَلَكَ أَسْلَمْتُ سَجَدَ وَجْهِي لِلَّذِي خَلَقَهُ وَصَوَّرَهُ وَشَقَّ سَمْعَهُ وَبَصَرَهُ تَبَارَكَ اللَّهُ أَحْسَنُ الْخَالِقِينَ ‏"‏ ‏.‏ ثُمَّ يَكُونُ مِنْ آخِرِ مَا يَقُولُ بَيْنَ التَّشَهُّدِ وَالتَّسْلِيمِ ‏"‏ اللَّهُمَّ اغْفِرْ لِي مَا قَدَّمْتُ وَمَا أَخَّرْتُ وَمَا أَسْرَرْتُ وَمَا أَعْلَنْتُ وَمَا أَسْرَفْتُ وَمَا أَنْتَ أَعْلَمُ بِهِ مِنِّي أَنْتَ الْمُقَدِّمُ وَأَنْتَ الْمُؤَخِّرُ لاَ إِلَهَ إِلاَّ أَنْتَ ‏"‏ ‏.‏
Reference : Sahih Muslim 771 a
In-book reference : Book 6, Hadith 240
USC-MSA web (English) reference : Book 4, Hadith 1695
  (deprecated numbering scheme)