Sahih Muslim 860
صحيح مسلم#860SahihA hadith like it has been narrated by Abu Huraira but for these words:" He (the man saying the prayer) does not know how much he has prayed
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: 4:23