This Hadith interprets the Marfu' Hadith [attributed to the Prophet (ﷺ)] of Abu Hurairah reported in the Sahihain:

On Friday, when the Imam is delivering the Khutbah (religious talk), if you say to your companion to keep quiet, then indeed you have committed a sin (error/something senseless).

حَدِيثَ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- فِي

اَلصَّحِيحَيْنِ

مَرْفُوعًا: { إِذَا قُلْتَ لِصَاحِبِكَ: أَنْصِتْ يَوْمَ اَلْجُمُعَةِ وَالْإِمَامِ يَخْطُبُ, فَقَدْ لَغَوْتَ } [1]‏ .‏