Musnad Ahmad 695:7

Ya'qub—meaning Ibn Ibrahim—narrated to us, my father narrated to us, from Al-Walid ibn Kathir, Muhammad ibn 'Amr ibn Halhalah ad-Du'ali narrated to me, that Ibn Shihab narrated to him, that 'Ali ibn al-Husayn narrated to him, that when they arrived in Medina from the presence of Yazid ibn Mu'awiyah after the killing of Husayn ibn 'Ali, Al-Miswar ibn Makhramah met him and said: "Do you have any need for me that you would command me to do?" He said: I said to him: "No." He said to him: "Will you give me the sword of the Messenger of Allah, may Allah bless him and grant him peace? For I fear that the people will overcome you and take it from you. And by Allah, if you give it to me, they will never reach it until my soul departs. Verily, 'Ali ibn Abi Talib sought the hand of the daughter of Abu Jahl while married to Fatimah, and I heard the Messenger of Allah, may Allah bless him and grant him peace, while he was addressing the people about that on this pulpit of his—and I was a youth reaching puberty at that time—saying: 'Verily, Fatimah is a piece of me, and I fear that she will be tempted in her religion.'" He said: Then he mentioned a son-in-law of his from Banu 'Abd Shams, and he praised him regarding his marriage to his daughter, and he spoke well. He said: "He spoke to me and was truthful, and he promised me and fulfilled it for me. And I do not forbid what is lawful, nor do I permit what is unlawful, but by Allah, the daughter of the Messenger of Allah, may Allah bless him and grant him peace, and the daughter of the enemy of Allah shall never be gathered together in one place."