Musannaf Ibn Abi Shaybah 34539 — The virtue of the Ansar

Thabit (may Allah have mercy on him) said that Abu Bakr bin Anas (may Allah have mercy on him) said: Sayyiduna Zayd bin Arqam (may Allah be pleased with him) wrote a letter to Sayyiduna Anas (may Allah be pleased with him) offering him condolences for his children and family who were martyred on the Day of al-Harrah. He (may Allah be pleased with him) wrote in his letter: I give you glad tidings from Allah which I heard from the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) said: "O Allah, forgive the Ansar, the children of the Ansar, the children of the children of the Ansar, the women of the Ansar, the women of the children of the Ansar, and also the women of the children of the children of the Ansar."