Musnad Ahmad 30:3759

Hammad ibn Khalid narrated to us, Mu'awiyah narrated to us, from Abu Bishr, the mu'adhdhin of the Damascus mosque, from 'Amir ibn Ludayn al-Ash'ari, who said: I asked Abu Hurayrah about fasting on the day of Friday, and he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The day of Friday is a day of 'Eid (festival), so do not make your day of 'Eid a day of fasting, unless you fast before it or after it."