If anyone hears him who makes the call to prayer and is not prevented from joining the congregation by any excuse--he was asked what an excuse consisted of and replied that it was fear or illness--the prayer he offers will not be accepted from him. (Using translation from Abū Dāʾūd 551)   

قَالَ رَسُولُ اللهِ ﷺ مَنْ سَمِعَ الْمُنَادِيَ فَلَمْ يَمْنَعْهُ مِنَ اتِّبَاعِهِ عُذْرٌ فَلَا صَلَاةَ لَهُ قَالُوا وَمَا الْعُذْرُ؟ قَالَ خَوْفٌ أَوْ مَرَضٌ  

The Prophet said: "Whoever hears the call and does not come, his prayer is not valid, except for those who have an excuse." (Using translation from Ibn Mājah 793)   

أَنَّ النَّبِيَّ ﷺ قَالَ مَنْ سَمِعَ النِّدَاءَ فَلَمْ يُجِبْ فَلَا صَلَاةَ لَهُ إِلَّا مِنْ عُذْرٍ  

[Machine] That Ibn Umar was invited on Friday while he was preparing for Friday prayer to Sa'id bin Zaid bin Amr bin Nufayl, and he was dying, so Ibn Umar went to him and left the Friday prayer.  

أَنَّ ابْنَ عُمَرَ دُعِيَ يَوْمَ الْجُمُعَةِ وَهُوَ يَسْتَجْهِزُ لِلْجُمُعَةِ إِلَى سَعِيدِ بْنِ زَيْدِ بْنِ عَمْرِو بْنِ نُفَيْلٍ وَهُوَ يَمُوتُ فَأَتَاهُ وَتَرَكَ الْجُمُعَةَ  

[Machine] That the daylight is rising and the Friday is approaching, and he left the Friday.  

أَنْ تَعَالَى النَّهَارُ وَاقْتَرَبَ الْجُمُعَةُ وَتَرَكَ الْجُمُعَةَ