Chapter 20: The Book of Invoking Curses
Sa' id b. Jubair reported that Mus' ab b. Zubair did not effect separation between the Mutala' inain (invokers of curses). Sa' id said: It was mentioned to 'Abdullah b. Umar (Allah be pleased with them) and he said: Allah' s Apostle (ﷺ) effected separation between the two members of Banu al-' Ajlan.
Sahih Muslim 1493f