Sahih al-Bukhari 444
صحيح البخاري#444SahihNarrated Abu Qatada Al-Aslami:Allah's Messenger (ﷺ) said, "If anyone of you enters a mosque, he should pray two rak`at before sitting
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: 8:93