Jami` at-Tirmidhi 3902
جامع الترمذي#3902SahihZaid bin Arqam wrote to Anas bin Malik, comforting him over those of his family and children of his paternal uncle who suffered on the day of Al-Harrah. So he wrote to him:"I give you glad tidings of good news from Allah. I heard the Messenger of Allah (ﷺ) say: 'O Allah forgive the Ansar and the children of the Ansar, and the children of their children
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih
In-book reference: 49:302