مُوَطَّأُ مَالِكٍ
Muwatta Malik 234
Jumu'a
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 Umar saw two men talking while the imam was giving the khutba on the day of jumua and he threw pebbles at them to tell them to be quiet.
Arabic/English book reference: Book 5, Hadith 9