Musnad Ahmad 26:172

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Ishaq, from Abu ‘Ubaydah, from ‘Abdullah, that the Prophet, peace and blessings of Allah be upon him, used to frequently say: "Glory be to You, our Lord, and with Your praise. O Allah, forgive me." He said: Then when "When the victory of Allah has come and the conquest" was revealed, he said: "Glory be to You, our Lord, and with Your praise. O Allah, forgive me, for You are the Accepting of repentance, the Merciful."