Mujahid (may Allah have mercy on him) narrates from Ibn Abbas (may Allah be pleased with them both) that he disliked speaking in four places: the two Eids, the rain prayer (istisqa), and Friday.
This is mawquf (it stops at the Companion).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة العيدين / 6222