Ali bin Abu Talib proposed to marry the daughter of Abu Jahl while he was already married to Fatimah. I heard the Messenger of Allah ﷺ addressing the people about this matter from this very pulpit of his, and I was a young man who had reached puberty at that time.He said, "Fatimah is a part of me, and I fear that she may be tested in her religion."Then he mentioned a son-in-law of his from Banu Abd Shams and praised him highly for the way he had conducted himself in their family relationship. He said, "He spoke to me and was truthful with me, and he made me a promise and fulfilled it. I do not forbid what is lawful, nor do I make lawful what is forbidden. But by Allah, the daughter of the Messenger of Allah ﷺ and the daughter of the enemy of Allah shall never be brought together in one place."
أن علي بن أبي طالب خطب بنت أبي جهل على فاطمة. فسمعت رسول الله ﷺ وهو يخطب الناس في ذلك، على منبره هذا، وأنا يومئذ محتلم، فقال: إن فاطمة مني، وإني أتخوف أن تفتن في دينها قال: ثم ذكر صهرا له من بني عبد شمس، فأثنى عليه في مصاهرته إياه فأحسن. قال: حدثني فصدقني ووعدني فأوفى لي. وإني لست أحرم حلالا ولا أحل حراما. ولكن والله لا تجتمع بنت رسول الله ﷺ وبنت عدو الله مكانا واحدا أبدا.
Bukhari related it in the chapter on the fifth of the spoils (3110), and Muslim in the virtues of the companions (2449-95), both of them through the route of Yaqub bin Ibrahim, who said, my father narrated to us, from Walid bin Kathir, who said, Muhammad bin Amr bin Halhala Duwali narrated to me, that Ibn Shihab told him that Ali bin Husayn told him, from Miswar bin Makhrama.He then mentioned it, and it contains a story. This is the wording of Muslim, and the wording of Bukhari is similar to it.