Prayer (Kitab Al-Salat)
2/242. Chapter:
Speaking While The Imam Delivers The Khutbah
Sunan Abi Dawud
حَدَّثَنَا الْقَعْنَبِيُّ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا قُلْتَ أَنْصِتْ وَالإِمَامُ يَخْطُبُ فَقَدْ لَغَوْتَ " .
Abu Hurairah reported the Messenger of Allah (ﷺ) as saying: When you tell (your brother on Friday) to be silent while the imam is giving the sermon you are guilty of idle talk.
Reference : Sunan Abi Dawud 1112In-book reference : Book 2, Hadith 723English translation : Book 2, Hadith 1107