He heard the Messenger of Allah ﷺ say, "People, turn in repentance to your Lord, for I myself repent to Him a hundred times a day."
حدثنا يحيى بن سعيد حدثنا شعبة قال حدثنا عمرو بن مرة قال سمعت أبا بردة قال سمعت الأغر رجلا من جهينة يحدث
أنه سمع رسول الله ﷺ يقول يا أيها الناس توبوا إلى ربكم فإني أتوب إليه في اليوم مائة مرة
Its isnad is sahih, all its narrators being reliable and already mentioned previously. Muslim narrated it, 4/2075, no. 2702, in the Book of Remembrance, on the recommendation of seeking forgiveness and doing so frequently. Abu Dawud also narrated it similarly, 2/177, no. 1515, in the Book of Prayer. Also Tabarani in Al-Kabir, 1/302, no. 887, and Bayhaqi, 7/52.