سنن ابن ماجه

It was narrated that Kuraib the freed slave of ‘Abdullah bin ‘Abbas said: “A son of ‘Abdullah bin ‘Abbas died, and he said to me: ‘O Kuraib! Get up and see if anyone has assembled (to pray) for my son.’ I said: ‘Yes.’ He said: ‘Woe to you, how many do you see? Forty?’ I said: ‘No, rather there are more.’ He said: ‘Take my son out, for I bear witness that I hear the Messenger of Allah (ﷺ) say: “No (group of) forty believers intercede for a believer, but Allah will accept their intercession.”