Musnad Ahmad 31:358

Hashim ibn al-Qasim narrated to us, Isra'il narrated to us, from Jabir, from 'Amir, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no prayer after the Fajr [prayer] until the sun rises, and no [prayer] after the 'Asr [prayer] until the sun sets. And there is no fasting on the day of al-Fitr nor on the day of al-Adha."