Musnad Ahmad 30:906

'Abd al-Rahman narrated to us, from Mu'awiyah—meaning Ibn Salih—from Abu Bishr, from 'Amir ibn Ludayn al-Ash'ari, from Abu Hurayrah, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "Indeed, the day of Friday is a day of celebration (Eid), so do not make the day of your celebration a day of your fasting, unless you fast a day before it or after it."