Sahih al-Bukhari 825
صحيح البخاري#825SahihNarrated Sa`id bin Al-Harith:Abu Sa`id led us in the prayer and said the Takbir aloud on arising from the prostration, and on prostrating, on rising again, and on getting up from the second rak`a. Abu Sa`id said, "I saw the Prophet doing the same
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 10:219