وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، رَأَى رَجُلَيْنِ يَتَحَدَّثَانِ وَالإِمَامُ يَخْطُبُ يَوْمَ الْجُمُعَةِ فَحَصَبَهُمَا أَنِ اصْمُتَا ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umarsaw two men talking while the imam was giving the khutba on the day ofjumua and he threw pebbles at them to tell them to be quiet. Translation Not Available

Book Ref: Muwatta Imam Malik Book 5 Hadith 234
Web Ref:  Muwatta Imam Malik Book 5 Hadith 9