once
((عَنِ ابْنِ عُمَرَ رضي الله عنه قَاَلَ: كَانَ يُعَدُّ لِرَسُولِ اللَّهِ صلى الله عليه وسلم فِي الْمَجْلِسِ الوَاحِدِ مِائَةُ مَرَّةٍ مِنْ قَبْلِ أَنْ يَقُومَ: ((رَبِّ اغْفِرْ لِي، وَتُبْ عَلَيَّ، إِنَّكَ أَنْتَ التَّوَّابُ الغَفُورُ)).
Edition transliteration
Ibn AAumar said: It would be counted that the Messenger of Allah would say one hundred times at any one sitting before getting up: (Rabbigh-fir lee watub AAalay, innaka antat-tawwabul-ghafoor.)
Meaning
Ibn AAumar said: It would be counted that the Messenger of Allah would say one hundred times at any one sitting before getting up: (O my Lord, forgive me and turn towards me (to accept my repentance). Verily You are The Oft-Returning. The Oft-Forgiving.)
Source and references
Hisn al-Muslim, entry 195.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗