Musnad Ahmad 31:524

Waki’ narrated to us, Sufyan narrated to us, from Qays ibn Muslim, from Tariq ibn Shihab, who said: The first to begin with the sermon on the day of Eid before the prayer was Marwan ibn al-Hakam. A man stood up to him and said: "The prayer is before the sermon." Marwan said: "That which was there has been abandoned, O Abu so-and-so." Abu Sa’id al-Khudri said: "As for this one, he has fulfilled what was upon him. I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'Whoever among you sees an evil, let him change it with his hand; if he is not able, then with his tongue; and if he is not able, then with his heart, and that is the weakest of faith.'"