It was narrated that Ubayy bin Ka’b said:

“The Messenger of Allah (ﷺ) said: ‘For guarding the frontier for a day in the cause of Allah, defending the Muslims, seeking reward, apart from in the month of Ramadan, there is a reward granted greater than worshipping for a hundred years, fasting and praying. Guarding the frontier for a day in the cause of Allah, defending the Muslims, seeking reward, in the month of Ramadan, is better before Allah and brings a greater reward” – I think he said – “than worshipping for a thousand years, fasting and praying. If Allah returns him to his family safe and sound, no bad deed will be recorded for him for a thousand years, but his good deeds will be recorded, and the reward for guarding the frontier will come to him until the Day of Resurrection.”

حَدَّثَنَا مُحَمَّدُ بْنُ إِسْمَاعِيلَ بْنِ سَمُرَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ يَعْلَى السُّلَمِيُّ، حَدَّثَنَا عُمَرُ بْنُ صُبْحٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَمْرٍو، عَنْ مَكْحُولٍ، عَنْ أُبَىِّ بْنِ كَعْبٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏

‏ لَرِبَاطُ يَوْمٍ فِي سَبِيلِ اللَّهِ مِنْ وَرَاءِ عَوْرَةِ الْمُسْلِمِينَ مُحْتَسِبًا مِنْ غَيْرِ شَهْرِ رَمَضَانَ أَعْظَمُ أَجْرًا مِنْ عِبَادَةِ مِائَةِ سَنَةٍ صِيَامِهَا وَقِيَامِهَا وَرِبَاطُ يَوْمٍ فِي سَبِيلِ اللَّهِ مِنْ وَرَاءِ عَوْرَةِ الْمُسْلِمِينَ مُحْتَسِبًا مِنْ شَهْرِ رَمَضَانَ أَفْضَلُ عِنْدَ اللَّهِ وَأَعْظَمُ أَجْرًا - أُرَاهُ قَالَ - مِنْ عِبَادَةِ أَلْفِ سَنَةٍ صِيَامِهَا وَقِيَامِهَا فَإِنْ رَدَّهُ اللَّهُ إِلَى أَهْلِهِ سَالِمًا لَمْ تُكْتَبْ عَلَيْهِ سَيِّئَةٌ أَلْفَ سَنَةٍ وَتُكْتَبُ لَهُ الْحَسَنَاتُ وَيُجْرَى لَهُ أَجْرُ الرِّبَاطِ إِلَى يَوْمِ الْقِيَامَةَ ‏

‏ ‏.‏