Narrated Ibn `Abbas:
`Umar used to admit me (into his house) along with the old men who had fought in the Badr battle. Some of them said (to `Umar), "Why do you allow this young man to enter with us, while we have sons of his own age? " `Umar said, "You know what person he is." One day `Umar called them and called me along with them, I had thought he called me on that day to show them something about me (i.e. my knowledge). `Umar asked them, "What do you say about (the Sura): "When comes the help of Allah and the Conquest (of Mecca) And you see mankind entering the Religion of Allah (i.e. Islam) in crowds. 'So celebrate the Praises Of your Lord and ask for His forgiveness, Truly, He is the One Who accepts repentance and forgives." (110.1-3) Some of them replied, "We are ordered to praise Allah and repent to Him if we are helped and granted victory." Some said, "We do not know." Others kept quiet. `Umar then said to me, "Do you say similarly?" I said, "No." `Umar said "What do you say then?" I said, "This Verse indicates the approaching of the death of Allah's Messenger (ﷺ) of which Allah informed him. When comes the help of Allah and the Conquest, i.e. the Conquest of Mecca, that will be the sign of your Prophet's) approaching death, so testify the uniqueness of your Lord (i.e. Allah) and praise Him and repent to Him as He is ready to forgive." On that, `Umar said, "I do not know about it anything other than what you know."
'A'isha reported: The Messenger of Allah (ﷺ) recited often these words: Hallowed be Allah and with His praise, I seek the forgiveness of Allah and return to Him. She said: I asked: Messenger of Allah, I see that you often repeat the saying" subhan allahi bihamdihi astag firullahi watubuilaih" whereupon he said: My Lord informed me that I would soon see a sign in my Ummah, so when I see it I often recite (these) words: Hallowed be Allah and with His Praise, I seek forgiveness of Allah and return to Him. Indeed I saw it (when this verse) was revealed:" When Allah's help and victory came, it marked the victory of Mecca, and you see people entering into Allah's religion in troops, celebrate the praise of Thy Lord and ask His forgiveness. Surely He is ever returning to Mercy."