It is narrated from Abu Huraira (may Allah be pleased with him) that the Prophet (peace be upon him) said: "When the Imam is delivering the sermon and you say to your companion sitting beside you, 'Be quiet,' then you yourself have engaged in idle (useless) talk."
Hadith Referenceمسند الإمام الشافعي / كتاب الجمعة / 427
It is narrated from Abu Huraira (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When you say to your companion 'Be quiet' while the Imam is delivering the sermon on the day of Jumu'ah, then you have engaged in idle talk yourself."
Hadith Referenceمسند الإمام الشافعي / كتاب الجمعة / 428
Through another chain, it is narrated from Abu Hurairah (may Allah be pleased with him) from the Prophet ﷺ in a similar manner, but in it, instead of ﴿لَغَوْتَ﴾, it is ﴿لَغَيْتَ﴾. Imam Ibn ‘Uyaynah (may Allah have mercy on him) says: ﴿لَغَيْتَ﴾ is the dialect of Abu Hurairah (may Allah be pleased with him).
Hadith Referenceمسند الإمام الشافعي / كتاب الجمعة / 429
Hadith Takhrijاخرجہ مسلم، الجمعۃ، باب فی الإنصات یوم الجمعۃ فی الخطبۃ، رقم : 851۔