[Machine] The Messenger of Allah ﷺ used to deliver two sermons on Fridays, with a sitting session in between them.  

كَانَ رَسُولُ اللهِ ﷺ يَخْطُبُ يَوْمَ الْجُمُعَةِ خُطْبَتَيْنِ بَيْنَهُمَا جِلْسَةٌ  

[Machine] That the Prophet ﷺ delivered it and Mu'adh bin Jabal collected it with the Muslims. Mus'ab bin Umair said: It reached us that there is no Jumu'ah (Friday prayer) except with a sermon. So whoever does not give a sermon, then he should pray four (rak'ahs).  

أَنْ يَقْدُمَهَا رَسُولُ اللهِ ﷺ فَجَمَّعَ بِالْمُسْلِمِينَ مُصْعَبُ بْنُ عُمَيْرٍ قَالَ وَبَلَغَنَا أَنَّهُ لَا جُمُعَةَ إِلَّا بِخُطْبَةٍ فَمَنْ لَمْ يَخْطُبْ صَلَّى أَرْبَعًا  

[Machine] If the imam does not give a sermon on Friday, then he prays four units (rak'ahs) and we have been informed about that from Ata ibn Abi Rabah and others, and from Saeed ibn Jubair who said: "Friday used to be four (rak'ahs) but the sermon was made in place of the two units of prayer."  

إِذَا لَمْ يَخْطُبِ الْإِمَامُ يَوْمَ الْجُمُعَةِ صَلَّى أَرْبَعًا وَرُوِّينَا ذَلِكَ عَنْ عَطَاءِ بْنِ أَبِي رَبَاحٍ وَغَيْرِهِ وَعَنْ سَعِيدِ بْنِ جُبَيْرٍ قَالَ كَانَتِ الْجُمُعَةُ أَرْبَعًا فَجُعِلَتِ الْخُطْبَةُ مَكَانَ الرَّكْعَتَيْنِ