Sahih Muslim 1568
صحيح مسلم#1568SahihQatada narrated on the authority of Anas b. Malik that the Messenger of Allah (ﷺ) said:He who forgets the prayer, or he slept (and it was omitted), its expiation is (only) that he should observe it when he remembers it
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: 5:401