Ibn Hibban

Abu Bakr bin Anas narrates: Sayyiduna Zaid bin Arqam (may Allah be pleased with him) wrote a letter to Sayyiduna Anas bin Malik (may Allah be pleased with him) in which he offered condolences regarding his children and family members who were martyred in the incident of Harrah. In his letter, he wrote this: I give you glad tidings of that which is from Allah Almighty. I heard the Noble Prophet (peace and blessings be upon him) say: "O Allah! Forgive the Ansar, the sons of the Ansar, the sons of the sons of the Ansar, the women (wives) of the Ansar, the women (wives) of the sons of the Ansar, and the women (wives) of the sons of the sons of the Ansar."