Ali bin Abi Talib narrated that whenever the Messenger of Allah would stand for Salat, he would say:

“I have directed my face towards the One who has created the heavens and the earth, as a Hanif, and I am not of the idolaters. Indeed, my Salat, my sacrifice, my living, my dying, is for Allah, the Lord of all that exists, without partner, and with this have I been ordered and I am of the Muslims. O Allah, You are the King, there is none worthy of worship except You. You are My Lord, and I am Your slave, I have wronged myself and I admit to my sin, so forgive me all my sins, verily, there is none who forgives sins but You, and guide me to the best of manners, none guides to the best of them except You, and turn away from me the evil of them, none can turn away from me the evil of them, none can turn away from me the evil of them except You. Here I am in obedience to You, and in aiding Your cause, and the good, all of it is in Your Hands, and the evil is not attributed to You, I am reliant upon You and ever-turning towards You, Blessed are You and Exalted are You I seek Your forgiveness and I repent to you (Wajjahtu Wajhi Lilladhi Fataras-Samawati Wal-Arda Hanifan Wa Ma Ana Min Al-Mushrikin, Inna Salati Wa Nusuki Wa Mahyaya Wa Mamati Lillahi Rabbil-Alamin, La Sharika Lahu Wa Bidhalika Umirtu Wa Ana Min Al-Muslimin. Allahumma Antal-Maliku La Ilaha Illa Ant, Anta Rabbi, Wa ana Abduka Zalamtu Nafsi Wa’taraftu Bidhanbi Faghfirli Dhanbi Jami’an, Innahu La Yaghfir Agh-Dhunuba Illa Ant. Wahdini Li-Ahsanil-Alkhlaqi La Yahdi Li-Ahsaniha Illa Ant. Wasrif Anni Sayy’aha, La Yasrifu Anni Sayy’aha Illa Ant. Labaika Wa Sa’daika Wal-Khairu Kulluhu Fi Yadaika, Wash-Sharru Laisa Ilaik, Tabarakta Wa Ta’alaita Astaghfiruka Wa Atubu Ilaik).” And when he would bow in Ruku he would say: “O Allah, to You have I bowed, and in You have I believed, and to You have I submitted. My hearing, my sight, my bones, and my sinew are humbled to you (Allahumma Laka Raka’tu Wa Bika Amantu Wa Laka Aslamtu Khasha’a Laka Sam’I Wa Basari Wa Asmi, Wa Asbi).” And when he would rise he would say: “O Allah, our Lord, to You is praise filling the heaven and filling the earth, and filling what is between them, and filling whatever You have wished of things afterward (Allahumma Rabbana Lakal-Hamdu Mil’as-Samawati Wa Mil’al-Ard Wa Mil’a Ma Bainahuma, Wa Mil’a Ma Shi’ta Min Shai’in Ba’d).” Then, when he prostrated, he would say: “O Allah, to You have I prostrated, and in You have I believed, and to You have I submitted (in Islam), my face has prostrated to the One Who created it, and fashioned it, and gave it its hearing and sight, [so] Blessed is Allah, the Best of Creators (Allahumma Laka Sajadtu Wa Bika Amantu Wa Laka Aslamtu, Sajada Wajhi Lilladhi Khalaqahu Fa Sawwarahu Wa Shaqqa Sam’ahu Wa Basarahu Fatabarak Allahu Ahsanul-Khaliqin).” Then the last of what he would say between At-Tashahud and At-Taslim was: “O Allah, forgive me what I have done, before and after, and what I have hidden, and what I have done openly, and what I have transgressed the limit in, and what You know about more than me, You are the One Who sends forth and the One Who delays, there is none worthy of worship except You (Allahummaghfirli Ma Qaddamtu Wa Ma Akhkhartu Wa Ma Asrartu A’laantu Wa Ma Wa Ma Asraftu, Wa Ma Anta A’lamu Bihi Minni, Antal-Muqaddimu Wa Antal-Mu’akhkhiru, La Ilaha Illa Ant).”

حَدَّثَنَا الْحَسَنُ بْنُ عَلِيٍّ الْخَلاَّلُ، حَدَّثَنَا أَبُو الْوَلِيدِ الطَّيَالِسِيُّ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ أَبِي سَلَمَةَ، وَيُوسُفُ بْنُ الْمَاجِشُونِ، قَالَ عَبْدُ الْعَزِيزِ حَدَّثَنِي عَمِّي، وَقَالَ، يُوسُفُ أَخْبَرَنِي أَبِي، حَدَّثَنِي الأَعْرَجُ، عَنْ عُبَيْدِ اللَّهِ بْنِ أَبِي رَافِعٍ، عَنْ عَلِيِّ بْنِ أَبِي طَالِبٍ، أَنَّ رَسُولَ اللَّهِ ﷺ 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 " . فَإِذَا رَكَعَ قَالَ " اللَّهُمَّ لَكَ رَكَعْتُ وَبِكَ آمَنْتُ وَلَكَ أَسْلَمْتُ خَشَعَ لَكَ سَمْعِي وَبَصَرِي وَعِظَامِي وَعَصَبِي " . فَإِذَا رَفَعَ قَالَ " اللَّهُمَّ رَبَّنَا لَكَ الْحَمْدُ مِلْءَ السَّمَاءِ وَمِلْءَ الأَرْضِ وَمِلْءَ مَا بَيْنَهُمَا وَمِلْءَ مَا شِئْتَ مِنْ شَيْءٍ بَعْدُ " . فَإِذَا سَجَدَ قَالَ " اللَّهُمَّ لَكَ سَجَدْتُ وَبِكَ آمَنْتُ وَلَكَ أَسْلَمْتُ سَجَدَ وَجْهِي لِلَّذِي خَلَقَهُ فَصَوَّرَهُ وَشَقَّ سَمْعَهُ وَبَصَرَهُ فَتَبَارَكَ اللَّهُ أَحْسَنُ الْخَالِقِينَ " . ثُمَّ يَقُولُ 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 " . قَالَ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .