كتاب الجمعة
7
The Book of Prayer - Friday
(8)
Chapter: The virtue of one who remains silent and listens attentively during the khutbah
(8)
باب فَضْلِ مَنِ اسْتَمَعَ وَأَنْصَتَ فِي الْخُطْبَةِ ‏

Abu-Huraira reported Allah's Apostle (ﷺ) as saying:

He who took a bath and then came for Jumu'a prayer and then prayed what was fixed for him, then kept silence till the Imam finished the sermon, and then prayed along with him, his sins between that time and the next Friday would be forgiven, and even of three days more.
حَدَّثَنَا أُمَيَّةُ بْنُ بِسْطَامٍ، حَدَّثَنَا يَزِيدُ، - يَعْنِي ابْنَ زُرَيْعٍ - حَدَّثَنَا رَوْحٌ، عَنْ سُهَيْلٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ مَنِ اغْتَسَلَ ثُمَّ أَتَى الْجُمُعَةَ فَصَلَّى مَا قُدِّرَ لَهُ ثُمَّ أَنْصَتَ حَتَّى يَفْرُغَ مِنْ خُطْبَتِهِ ثُمَّ يُصَلِّيَ مَعَهُ غُفِرَ لَهُ مَا بَيْنَهُ وَبَيْنَ الْجُمُعَةِ الأُخْرَى وَفَضْلَ ثَلاَثَةِ أَيَّامٍ ‏"‏ ‏.‏
Reference : Sahih Muslim 857 a
In-book reference : Book 7, Hadith 37
USC-MSA web (English) reference : Book 4, Hadith 1867
  (deprecated numbering scheme)