Sahih al-Bukhari 650
صحيح البخاري#650SahihNarrated Salim:I heard Um Ad-Darda' saying, "Abu Ad-Darda' entered the house in an angry mood. I said to him. 'What makes you angry?' He replied, 'By Allah! I do not find the followers of Muhammad doing those good things (which they used to do before) except the offering of congregational prayer." (This happened in the last days of Abu Ad-Darda' during the rule of `Uthman)
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: 10:47