Chapter 39: Battles (Kitab Al-Malahim)
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 Abu Hurayrah"?He (Abu Hurayrah) said: I heard my friend Abul Qasim (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.
Sunan Abi Dawud 4308