Sahih al-Bukhari 1205
صحيح البخاري#1205SahihNarrated Anas bin Malik: While Abu Bakr was leading the people in the morning prayer on a Monday, the Prophet (ﷺ) came towards them suddenly having lifted the curtain of 'Aisha's house, and looked at them as they were standing in rows and smiled. Abu Bakr tried to come back thinking that Allah's Apostle wanted to come out for the prayer. The attention of the Muslims was diverted from the prayer because they were delighted to see the Prophet. The Prophet (ﷺ) waved his hand to them to complete their prayer, then he went back into the room and let down the curtain. The Prophet expired on that very day
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: 21:9