A man from Banu Asad b. Khuzaimah asked Abu Ayyub al-Ansari: if one of us prays in his house, then comes to the mosque and finds that the iqamah is being called, and if I pray along with them ( in congregation), I feel something inside about it. Abu Ayyub replied: We asked the Prophet (ﷺ) about it. He said: That is a share from the spoils received by the warriors (i.e. he will receive double the reward of the prayer).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَحْمَدُ بْنُ صَالِحٍ، قَالَ قَرَأْتُ عَلَى ابْنِ وَهْبٍ قَالَ أَخْبَرَنِي عَمْرٌو، عَنْ بُكَيْرٍ، أَنَّهُ سَمِعَ عَفِيفَ بْنَ عَمْرِو بْنِ الْمُسَيَّبِ، يَقُولُ حَدَّثَنِي رَجُلٌ، مِنْ بَنِي أَسَدِ بْنِ خُزَيْمَةَ أَنَّهُ سَأَلَ أَبَا أَيُّوبَ الأَنْصَارِيَّ فَقَالَ يُصَلِّي أَحَدُنَا فِي مَنْزِلِهِ الصَّلاَةَ ثُمَّ يَأْتِي الْمَسْجِدَ وَتُقَامُ الصَّلاَةُ فَأُصَلِّي مَعَهُمْ فَأَجِدُ فِي نَفْسِي مِنْ ذَلِكَ شَيْئًا . فَقَالَ أَبُو أَيُّوبَ سَأَلْنَا عَنْ ذَلِكَ النَّبِيَّ صلى الله عليه وسلم فَقَالَ " ذَلِكَ لَهُ سَهْمُ جَمْعٍ " .
sunnah.com