Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: When the Imam is delivering the Friday sermon and you say to the person sitting next to you, "Be quiet," then you yourself have engaged in a useless act.
Hadith Referenceاللؤلؤ والمرجان / كتاب الجمعة / 494
Hadith Gradingمحدثین:«صحیح»
Hadith Takhrij«صحیح، أخرجه البخاري في: 11 كتاب الجمعة: 36 باب الإنصات يوم الجمعة والإمام يخطب»