Sahih Muslim 1746
صحيح مسلم#1746SahihZaid b. Arqam, on seeing some people praying in the forenoon, said:They well know that prayer at another time than this is more excellent, for Allah's Messenger (ﷺ) said: The prayer of those who are penitent is observed when your weaned camels feel the heat of the sun
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: 6:175