Sahih al-Bukhari 4493
صحيح البخاري#4493SahihNarrated Ibn `Umar:While some people were at Quba (offering) morning prayer, a man came to them and said, "Last night Qur'anic Verses have been revealed whereby the Prophet (ﷺ) has been ordered to face the Ka`ba (at Mecca), so you too should face it." So they, keeping their postures, turned towards the Ka`ba. Formerly the people were facing Sham (Jerusalem) (Allah said):-- "And from whence-so-ever you start forth (for prayers), turn your face in the direction of the Sacred Mosque of Mecca (Al-Masjid-ul-Haram), and whence-so-ever you are, turn your face towards it (when you pray)
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: 65:20