Musnad Ahmad 30:854

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, he said: I heard ‘Ali ibn Zayd and Yunus ibn ‘Ubayd narrating from ‘Ammar, the freed slave of Banu Hashim, from Abu Hurayrah—as for ‘Ali, he attributed it to the Prophet, may Allah bless him and grant him peace, and as for Yunus, he did not go beyond Abu Hurayrah—that he said regarding this verse: {And a witness and what is witnessed} [Al-Buruj: 3]: He said—meaning—: "The witness is the Day of ‘Arafah, and the Promised Day is the Day of Resurrection."