Sahih al-Bukhari 6551
صحيح البخاري#6551SahihNarrated Abu Huraira: The Prophet (ﷺ) said, "The width between the two shoulders of a Kafir (disbeliever) will be equal to the distance covered by a fast rider in three days
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: 81:140