´It was narrated from Tha'labah bin Zahdam that:` 'Ali appointed Abu Mas'ud over the people, then went out on the day of 'Eid and said: 'O people, it is not part of the sunnah to pray before the imam.'"
Hadith ReferenceSunan an-Nasa'i / The Book of the Prayer for the Two 'Eids / Hadith: 1562
Hadith Gradingالألبانی:صحيح الإسناد | زبیر علی زئی:حسن