Reference : Hisn al-Muslim 249

وَقَالَ صلى الله عليه وسلم: (يَا أَيُّهَا النَّاسُ تُوبُوا إِلَى اللَّهِ فَإِنِّي أَتُوبُ فِي الْيَوْمِ إِلَيْهِ مِائَةَ مَرَّةٍ)
--

Allah's Messenger (ﷺ) said: "O people, repent to Allah, for I verily repent to Him one hundred times a day.

Reference:
Muslim 4/2076.

Chapter: Seeking forgiveness and repentance