Sahih Muslim 2199
صحيح مسلم#2199SahihAbdullah b. 'Abbas reported that his son died in Qudaid or 'Usfan. He said to Kuraib to see as to how many people had gathered there for his (funeral). He (Kuraib) said:So I went out and I informed him about the people who had gathered there. He (Ibn 'Abbas) said: Do you think they are forty? He (Kuraib) said: Yes. Ibn 'Abbas then said to them: Bring him (the dead body) out for I have heard Allah's Messenger (ﷺ) as saying: If any Muslim dies and forty men who associate nothing with Allah stand over his prayer (they offer prayer over him), Allah will accept them as intercessors for him
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: 11:77