The Prophet ﷺ said whoever makes wuḍūʾ well, comes to Jumuʿah, listens and stays silent, is forgiven what is between it and the next Jumuʿah, and three days more. (Muslim). And: “If you say to your companion ‘Be quiet’ while the imam is giving the khuṭbah, you have engaged in idle talk.” (al-Bukhārī).
العربية: عن أبي هريرة رضي الله عنه أنّ رسول الله ﷺ قال: «إذا قلتَ لصاحبك يوم الجمعة: أنصِت، والإمام يخطب، فقد لغوت». (البخاري).
During the khuṭbah: no talking, no phone — listen and reflect.