Sahih Muslim 1471
صحيح مسلم#1471SahihAbu'l-'Aliyat al-Bara' reported:I said to 'Abdullah b. Samit: We say our Jumu'a prayer behind those rulers who defer the prayer. He ('Abdullah b. Samit), struck. my thigh that I felt pain and said: I asked Abu Dharr about it, he struck my thigh and said: I asked the Messenger of Allah (ﷺ) about it. Upon this he said: Observe prayer at its prescribed time, and treat prayer along with them (along with those Imams who deter prayer) as Nafl. 'Abdullah said: It was narrated to me that the Messenger of Allah (ﷺ) struck the thigh of Abd Dharr
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: 5:304