Sahih al-Bukhari 3726
صحيح البخاري#3726SahihNarrated Sa`d:No doubt, (for some time) I stood for one-third of the Muslims
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: 62:73