Abu Dawud Book 32, Hadith Number 4294.

Narated By AbuHurayrah : 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 (AbuHurayrah) said: I heard my friend AbulQasim (PBUH) 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.