Sahih Muslim 2631
صحيح مسلم#2631SahihAbu Darda' reported:We were with the Messenger of Allah (ﷺ) on some of his journeys on an intensely hot day so much so that a person would place his hand on his head (in order to protect himself) against excessive heat, and none amongst us was fasting but the Messenger of Allah (ﷺ) and Abdullah b. Rawaha
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 13:137