Musnad Abu Ya'la al-Mawsili 129:124

Zuhayr narrated to us, Yazid ibn Harun narrated to us, Humayd informed us, from Anas, who said: The Messenger of Allah (may Allah bless him and grant him peace) arrived in Medina, and they had two days in which they would play. The Messenger of Allah (may Allah bless him and grant him peace) said: "I have come to you, and you have two days in which you play, but Allah has replaced them for you with two days better than them: the day of al-Fitr and the day of al-Nahr."