Sunan Abu Dawud
1516
Sahih+3

Narrated Abdullah ibn Umar: We counted that the Messenger of Allah (ﷺ) would say a hundred times during a meeting: "My Lord, forgive me and pardon me; Thou art the Pardoning and forgiving One

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid