Sahih Muslim 848
صحيح مسلم#848SahihAbu Sa'id al-Khudri reported:When you hear the call (to prayer), repeat what the Mu'adhdhin pronounces
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: 4:12