عَنْ زَاذَانَ عَنْ رَجُلٍ مِنْ أَصْحَابِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ مِنَ الْأَنْصَارِ أَنَّهُ سَمِعَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فِي صَلَاةٍ وَهُوَ يَقُولُ: ((رَبِّ اغْفِرْ لِي)) قَالَ شُعْبَةُ: أَوْ قَالَ: ((اللَّهُمَّ اغْفِرْ لِي وَتُبْ عَلَيَّ إِنَّكَ أَنْتَ التَّوَّابُ الْغَفُورُ)) مِائَةَ مَرَّةٍ
It is narrated from an Ansari Companion of the Messenger of Allah (may Allah be pleased with him) that he heard the Noble Prophet (peace and blessings be upon him) reciting this supplication in prayer: "O Allah! Forgive me and accept my repentance, indeed You are the Acceptor of repentance, the Most Forgiving." (O Allah! Forgive me and accept my repentance, for You alone are the Acceptor of repentance, the Most Forgiving.) The Prophet (peace and blessings be upon him) recited this supplication one hundred times.