Sahih Muslim 1087
صحيح مسلم#1087SahihA'isha reported:Never did I, see the Messenger of Allah (ﷺ) after the revelation (of these verses):" When Allah's help and victory came." observin- his prayer without making (this supplication) or he said in it (supplication): Hallowed be Thee, my Lord, and with Thy praise, O Allah, forgive me
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 4:249