Sahih Muslim 2074
صحيح مسلم#2074SahihAnas reported:I saw the Messenger of Allah (ﷺ) raising his hands (high enough) in supplication (for rain) that the whiteness of his armpits became visible
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: 9:5