Musannaf Ibn Abi Shayba 33:847

Ghundar narrated to us, from Shu'bah, from 'Amr ibn Murrah, from Abu Burdah, who said: I heard al-Agharr—and he was one of the companions of the Prophet (may Allah bless him and grant him peace)—narrating to Ibn 'Umar. He said: The Messenger of Allah (may Allah bless him and grant him peace) says: "Repent to your Lord, for I repent to Him one hundred times a day."