Sahih Muslim 1624
صحيح مسلم#1624SahihSalim b. 'Abdullah reported that his father had said:I saw the Messenger of Allah (ﷺ) delaying the sunset prayer till he would combine it with the 'Isha' when he hastened to set out on a journey
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: 6:55