Sahih al-Bukhari 4703
صحيح البخاري#4703SahihNarrated Abu Sa`id Al-Mualla:While I was praying, the Prophet (ﷺ) passed by and called me, but I did not go to him till I had finished my prayer. When I went to him, he said, "What prevented you from coming?" I said, "I was praying." He said, "Didn't Allah say" "O you who believes Give your response to Allah (by obeying Him) and to His Apostle." (8.24) Then he added, "Shall I tell you the most superior Sura in the Qur'an before I go out of the mosque?" When the Prophet (ﷺ) intended to go out (of the Mosque), I reminded him and he said, "That is: "Al hamdu-li l-lahi Rabbil-`alamin (Surat-al-fatiha)' which is the seven oft repeated verses (Al-Mathani) and the Grand Qur'an which has been given to me
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: 65:225