Hadith 7:98
Al-Agharr al-Muzani reported God’s messenger as saying, “My heart is invaded by unmindfulness, and I ask God’s pardon a hundred times in the day.” Muslim transmitted it.
وَعَنِ الْأَغَرِّ الْمُزَنِيِّ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِنَّهُ لَيُغَانُ عَلَى قَلْبِي وَإِنِّي لَأَسْتَغْفِرُ اللَّهَ فِي الْيَوْم مائَة مرّة» . رَوَاهُ مُسلم
Original Reference: Mishkat al-Masabih 2324