Narrated `Aisha:
Aflah, the brother of Abi Al-Qu`ais, asked permission to visit me after the order of Al-Hijab was revealed. I said, "I will not permit him unless I take permission of the Prophet (ﷺ) about him for it was not the brother of Abi Al-Qu`ais but the wife of Abi Al-Qu`ais that nursed me." The Prophet (ﷺ) entered upon me, and I said to him, "O Allah's Messenger (ﷺ)! Aflah, the brother of Abi Al-Qu`ais asked permission to visit me but I refused to permit him unless I took your permission." The Prophet (ﷺ) said, "What stopped you from permitting him? He is your uncle." I said, "O Allah's Messenger (ﷺ)! The man was not the person who had nursed me, but the woman, the wife of Abi Al-Qu`ais had nursed me." He said, "Admit him, for he is your uncle. Taribat Yaminuki (may your right hand be saved)" `Urwa, the sub-narrator added: For that `Aisha used to say, "Consider those things which are illegal because of blood relations as illegal because of the corresponding foster relations."
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 319
Arabic reference: Book 65, Hadith 4796