Sahih Muslim 880
صحيح مسلم#880SahihAbu Huraira reported:The Messenger of Allah (ﷺ) said: He who said his prayer, but did not recite the opening chapter of al-Kitab, his prayer is incomplete. He repeated it thrice
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: 4:43