They heard the Prophet say on his pulpit: "People should desist from failing to attend the congregations, otherwise Allah will seal their hearts, and they will be among the negligent." (Using translation from Ibn Mājah 794)   

وَأَبَا هُرَيْرَةَ أَنَّهُمَا سَمِعَا رَسُولَ اللَّهِ ﷺ يَقُولُ وَهُوَ عَلَى أَعْوَادِ مِنْبَرِهِ «لَيَنْتَهِيَنَّ أَقْوَامٌ عَنْ وَدَعِهِمُ الْجُمُعَاتِ أَوْ لَيَخْتِمَنَّ اللَّهُ عَلَى قُلُوبِهِمْ ثُمَّ لَيَكُونُنَّ مِنَ الْغَافِلِينَ»  

“The Messenger of Allah ﷺ said: ‘Whoever abandons Friday (prayer) three times, for no necessary reason, Allah will place a seal over his heart.’” (Using translation from Ibn Mājah 1126)   

قَالَ رَسُولُ اللَّهِ ﷺ «مَنْ تَرَكَ الْجُمُعَةَ تَهَاوُنًا بِهَا طَبَعَ اللَّهُ عَلَى قَلْبِهِ»