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)
عَنِ ابْنِ عُمَرَ وَأَبِي هُرَيْرَةَ أَنَّهُمَا سَمِعَا رَسُولُ اللهِ ﷺ يَقُولُ عَلَى أَعْوَادِ مِنْبَرِهِ «لَيَنْتَهِيَنَّ أَقْوَامٌ عَنْ وَدْعِهِمُ الْجُمُعَاتِ أَوْ لَيُخْتَمَنَّ عَلَى قُلُوبِهِمْ ثُمَّ لَيَكُونَنَّ مِنَ الْغَافِلِينَ»