Hadith 2.76 (Al-Bukhaari)
Narrated Abu Sai’d Al-Khudri (radiallahu ‘anhu): The Prophet (sallallahu ‘alaihi wa sallam) used to proceed to the musalla on the days of Id-ul-Fitr and Id-ul-Adha; the first thing to begin with was the prayer and after that he would stand in front of the people and the people would keep sitting in their rows. Then he would preach to them, advise them and give them orders, (i.e. Khutba). And after that if he wished to send an army for an expedition, he would do so; or if he wanted to give an order, he would do so, and then depart. The people followed this tradition till I went out with Marwan, the Governor of Medina, for the prayer of Id-ul-Adha or Id-ul-Fitr.
When we reached the musalla, there was a pulpit made by Kathir bin As-Salt. Marwan wanted to get up on that pulpit before the prayer. I got hold of his clothes but he pulled them and ascended the pulpit and delivered the Khutba before the prayer. I said to him, “By Allah, you have changed (the Prophet’s tradition).” He replied, “O Abu Sa’id! Gone is that which you know.” I said, “By Allah! What I know is better than what I do not know.” Marwan said, “People do not sit to listen to our khutba after the prayer, so I delivered the khutbah before the prayer.”