Musannaf Ibn Abi Shayba 21:212

Abu Mu'awiyah narrated to us, from al-A'mash, from Masruq, from 'Aishah, who said: The Messenger of Allah (may Allah bless him and grant him peace) used to frequently say before he died: "Glory be to You, O Allah, and with Your praise; I seek Your forgiveness and I repent to You." She said: I said, "O Messenger of Allah, what are these words that you have introduced?" He said: "A sign has been set for me regarding my nation; when I see it, I say them: 'When the victory of Allah comes and the conquest...'"