Sahih Muslim 1505
صحيح مسلم#1505SahihAbu Sa'id al-Khudri reported that he went to the Messenger of Allah (ﷺ) and found him observing prayer on a mat and prostrating on that
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: 5:338