once
وَقَالَ صلى الله عليه وسلم: ((يَا أَيُّهَا النَّاسُ تُوبُوا إِلَى اللَّهِ فَإِنِّي أَتُوبُ فِي الْيَوْمِ إِلَيْهِ مِائَةَ مَرَّةٍ)).
Meaning
He also said: ‘O People, Repent! Verily I repent to Allah, a hundred times a day.
Source and references
Hisn al-Muslim, entry 249.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗