Musnad Ahmad 799:3

Muhammad ibn Ja'far narrated to us, Shu'bah informed us, and Hajjaj said: Shu'bah narrated to me, he said: I heard Ma'bad ibn Khalid narrating from Zayd ibn 'Uqbah, from Samurah ibn Jundub, "That the Messenger of Allah, peace and blessings of Allah be upon him, used to recite in the two Eids: 'Glorify the name of your Lord, the Most High' (Surah Al-A'la), and 'Has there reached you the report of the Overwhelming [Event]?' (Surah Al-Ghashiyah)."