Musnad Ahmad 1156:37

Abdullah ibn Numayr narrated to us, he said: Abd al-Malik—meaning Ibn Abi Sulayman—narrated to us, from Ata’ ibn Abi Rabah, he said: Someone who heard Umm Salamah narrated to me, mentioning that the Prophet, peace and blessings of Allah be upon him, was in her house. Fatimah came to him with a pot containing *khazirah* (a dish made of meat and flour), and she entered with it to him. He said to her: "Call your husband and your two sons." She said: So Ali, al-Husayn, and al-Hasan came, and they entered upon him. They sat eating from that *khazirah*, while he was on a sleeping place of his upon a dais, beneath which was a Khaybari cloak. She said: And I was praying in the chamber, then Allah, the Mighty and Majestic, revealed this verse: "Allah only intends to remove from you the impurity, O people of the [Prophet's] household, and to purify you with [extensive] purification" [Al-Ahzab: 33]. She said: So he took the remainder of the cloak and covered them with it. Then he brought out his hand and gestured with it toward the sky, then said: "O Allah, these are the people of my household and my special ones, so remove from them the impurity and purify them with purification. O Allah, these are the people of my household and my special ones, so remove from them the impurity and purify them with purification." She said: So I put my head into the house and said: "And am I with you, O Messenger of Allah?" He said: "You are upon good, you are upon good." Abd al-Malik said: And Abu Layla narrated to me, from Umm Salamah, the like of the hadith of Ata’, exactly. Abd al-Malik said: And Dawud ibn Abi Awf Abu al-Jahhaf narrated to me, from Shahr ibn Hawshab, from Umm Salamah, the like of it, exactly.