Musnad Ahmad 30:855

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Yunus, who said: I heard ‘Ammar, the freed slave of Banu Hashim, narrating from Abu Hurayrah, who said regarding this verse: {And a witness and a witnessed [day]} [Al-Buruj: 3]: "The witness is Friday, the witnessed is the Day of ‘Arafah, and the promised is the Day of Resurrection."