Sahih Ibn Khuzaymah

It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) that among the last supplications between the Tashahhud and Salam of the Prophet (peace and blessings be upon him) is this: « 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 » "O Allah, forgive my earlier and later sins, my hidden and open sins, and the wrong I have committed against myself, and those faults which You know better than I do. You are the One Who brings forward and the One Who puts back. There is no deity except You."

Sayyiduna Mihjan bin Adra’ (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) entered the mosque and suddenly saw a man who had completed his prayer and was supplicating in the Tashahhud with these words, « اللّهُـمَّ إِنِّـي أَسْأَلُـكَ يا اللهُ بِأَنَّـكَ الواحِـدُ الأَحَـد الصَّـمَدُ الَّـذي لَـمْ يَلِـدْ وَلَمْ يولَدْ، وَلَمْ يَكـنْ لَهُ كُـفُواً أَحَـد ، أَنْ تَغْـفِرْ لي ذُنـوبي إِنَّـكَ أَنْـتَ الغَفـورُ الرَّحِّـيم ». “O Allah, I ask You by virtue of that Allah Who is One, Self-Sufficient, Who neither begets nor is born, and there is none comparable to Him, that You forgive my sins. Indeed, You are Most Forgiving, Most Merciful.” (Upon hearing this supplication) the Noble Prophet (peace and blessings be upon him) said three times: “Indeed, he has been forgiven, indeed, he has been forgiven.”