Sahih al-Bukhari 398
صحيح البخاري#398SahihNarrated Ibn `Abbas:When the Prophet (ﷺ) entered the Ka`ba, he invoked Allah in each and every side of it and did not pray till he came out of it, and offered a two-rak`at prayer facing the Ka`ba and said, "This is the Qibla
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: 8:49