(12) باب اسْتِحْبَابِ الاِسْتِغْفَارِ وَالاِسْتِكْثَارِ مِنْهُ
Al-Agharr al-Muzani, who was one amongst the Companions (of the Holy Prophet) reported that Allah's Messenger (ﷺ) said:
There is (at times) some sort of shade upon my heart, and I seek forgiveness from Allah a hundred times a day.
Reference: Sahih Muslim 2702 a
In-book reference: Book 48, Hadith 52
USC-MSA web (English) reference(deprecated numbering scheme): Book 35, Hadith 6522