Salih ibn Dirham said:

We went on the pilgrimage and met a man who asked us: Is there a town near you called al-Ubullah? We said: Yes. He said: Is there any of you who will undertake to pray two or four rak'ahs on my behalf in the mosque of al-Ashshar, stating "they are on behalf of AbuHurayrah"? He (Abu Hurayrah) said: I heard my friend AbulQasim (ﷺ) say: On the Day of Resurrection Allah will raise martyrs from the mosque of al-Ashshar, who will be the only ones to rise with the martyrs of Badr. Abu Dawud said: This mosque is near the river.

حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنِي إِبْرَاهِيمُ بْنُ صَالِحِ بْنِ دِرْهَمٍ، قَالَ سَمِعْتُ أَبِي يَقُولُ، انْطَلَقْنَا حَاجِّينَ فَإِذَا رَجُلٌ فَقَالَ لَنَا إِلَى جَنْبِكُمْ قَرْيَةٌ يُقَالُ لَهَا الأُبُلَّةُ قُلْنَا نَعَمْ ‏.‏ قَالَ مَنْ يَضْمَنُ لِي مِنْكُمْ أَنْ يُصَلِّيَ لِي فِي مَسْجِدِ الْعَشَّارِ رَكْعَتَيْنِ أَوْ أَرْبَعًا وَيَقُولَ هَذِهِ لأَبِي هُرَيْرَةَ سَمِعْتُ خَلِيلِي أَبَا الْقَاسِمِ صلى الله عليه وسلم يَقُولُ ‏

‏ إِنَّ اللَّهَ يَبْعَثُ مِنْ مَسْجِدِ الْعَشَّارِ يَوْمَ الْقِيَامَةِ شُهَدَاءَ لاَ يَقُومُ مَعَ شُهَدَاءِ بَدْرٍ غَيْرُهُمْ ‏

‏ ‏.‏ قَالَ أَبُو دَاوُدَ هَذَا الْمَسْجِدُ مِمَّا يَلِي النَّهْرَ ‏.‏