We counted that the Messenger of Allah ﷺ would say a hundred times during a meeting: "My Lord, forgive me and pardon me; Thou art the Pardoning and forgiving One". (Using translation from Abū Dāʾūd 1516)  

إِنْ كُنَّا لَنَعُدُّ لِرَسُولِ اللهِ ﷺ فِي الْمَجْلِسِ الْوَاحِدِ مِائَةَ مَرَّةٍ يَقُولُ «رَبِّ اغْفِرْ لِي وَتُبْ عَلَيَّ إِنَّكَ أَنْتَ التَّوَّابُ الْغَفُورُ»  

[Machine] I was sitting with the Messenger of Allah ﷺ and I heard him seeking forgiveness one hundred times, saying, "O Allah, forgive me, have mercy on me, and accept my repentance. Verily, You are the Accepter of repentance, the Most Merciful." The narration is from Zuhayr's collection.  

كُنْتُ عِنْدَ رَسُولِ اللهِ ﷺ جَالِسًا فَسَمِعْتُهُ اسْتَغْفَرَ مِائَةَ مَرَّةٍ يَقُولُ «اللهُمَّ اغْفِرْ لِي وَارْحَمْنِي وَتُبْ عَلَيَّ إِنَّكَ أَنْتَ التَّوَّابُ الْغَفُورُ» حِفْظُ زُهَيْرٍ  

[Machine] He was sitting with the Messenger of Allah ﷺ and said, "O Allah, forgive me, for indeed You are the Accepter of Repentance, the Most Forgiving." He continued to count on his fingers one hundred times.  

أَنَّهُ كَانَ قَاعِدًا مَعَ رَسُولِ اللهِ ﷺ فَقَالَ «اللهُمَّ اغْفِرْ لِي إِنَّكَ أَنْتَ التَّوَّابُ الْغَفُورُ» حَتَّى عَدَّ الْعَادُّ فِي يَدِهِ مِائَةَ مَرَّةٍ  

[Machine] I asked the Prophet ﷺ , I said, "O Messenger of Allah, how do we seek forgiveness?" He said, "Say: 'O Allah, forgive us, have mercy on us, and accept our repentance. And mention a word with its meaning for us. Indeed, You are the Accepter of repentance, the Merciful." 10223 Muawiyah bin Salih informed us, Khaled informed us, Saeed bin Ziad informed me, I heard Suleiman bin Yasar narrating from Muslim bin Al-Sa'ib bin Khabbab, they said, "O Messenger of Allah, how do we seek forgiveness?" Similar to that.  

سَأَلْتُ النَّبِيَّ ﷺ قَالَ قُلْتُ يَا رَسُولَ اللهِ كَيْفَ نَسْتَغْفُرُ؟ قَالَ قُلِ اللهُمَّ اغْفِرْ لَنَا وَارْحَمْنَا وَتُبْ وَذَكَرَ كَلِمَةً مَعْنَاهَا عَلَيْنَا إِنَّكَ أَنْتَ التَّوَّابُ الرَّحِيمُ 10223 أَخْبَرَنَا مُعَاوِيَةُ بْنُ صَالِحٍ حَدَّثَنَا خَالِدٌ حَدَّثَنِي سَعِيدُ بْنُ زِيَادٍ سَمِعْتُ سُلَيْمَانَ بْنَ يَسَارٍ يُحَدِّثُ عَنْ مُسْلِمِ بْنِ السَّائِبِ بْنِ خَبَّابٍ قَالُوا يَا رَسُولَ اللهِ كَيْفَ نَسْتَغْفُرُ؟ نَحْوَهُ  

[Machine] On the authority of Muslim ibn As-Sa'ib ibn Khabbab, they said: "O Messenger of Allah, how do we seek forgiveness?" He said: "Say: 'O Allah, forgive us, have mercy on us, and accept our repentance. Indeed, You are the Accepter of repentance, the Merciful.'"  

عَنْ مُسْلِمِ بْنِ السَّائِبِ بْنِ خَبَّابٍ قَالُوا يَا رَسُولَ اللهِ كَيْفَ نَسْتَغْفُرُ؟ قَالَ قُولُوا اللهُمَّ اغْفِرْ لَنَا وَارْحَمْنَا وَتُبْ عَلَيْنَا إِنَّكَ أَنْتَ التَّوَّابُ الرَّحِيمُ