Sahih Muslim 1621
صحيح مسلم#1621SahihIbn 'Umar reported:When the Messenger of Allah (ﷺ) was in a state of hurry on a journey, he combined the sunset and 'Isha' prayers
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: 6:52