From Sahih Muslim (Hadith 6859):
Al-Agharr al-Muzani who was from amongst the Companions of Allah's Apostle (ﷺ) reported that Ibn 'Umar stated to him that Allah's Messenger (may peace 'be upon him) said:O people, seek repentance from Allah. Verily, I seek repentance from Him a hundred times a day
Reference: Muslim 6859