Ayesha said, "Aflah, the brother of Abu Quays, asked permission to enter upon me after the verse of the veil had been revealed. I said, 'I will not grant him permission until I ask the Prophet ﷺ about it, for it was not his brother Abu Quays who nursed me, but rather the wife of Abu Quays who nursed me.'Then the Prophet ﷺ entered upon me, and I said to him, 'Messenger of Allah, Aflah the brother of Abu Quays asked permission to enter, but I refused to admit him until I consulted you.'The Prophet ﷺ asked, 'What prevented you from admitting your uncle?'I replied, 'Messenger of Allah, the man himself did not nurse me. It was the wife of Abu Quays who nursed me.'He said, 'Admit him, for he is your uncle. May your hands be dusty.'"Urwa said, "That is why Ayesha used to say, 'Consider unlawful through nursing whatever you consider unlawful through lineage.'"
استأذن علي أفلح أخو أبي القعيس بعدما أنزل الحجاب فقلت: لا آذن له حتى أستأذن فيه النبي ﷺ فإن أخاه أبا القعيس ليس هو أرضعني، ولكن أرضعتني امرأة أبي القعيس، فدخل علي النبي ﷺ فقلت له: يا رسول الله إن أفلح أخا أبي القعيس استأذن فأبيت أن أذن له حتى أستأذنك، فقال النبي ﷺ: وما منعك أن تأذني عمك قلت: يا رسول الله، إن الرجل ليس هو أرضعني، ولكن أرضعتني امرأة أبي القعيس، فقال: ائذني له فإنه عمك تربت يمينك. قال عروة: فلذلك كانت عائشة تقول: حرموا من الرضاعة ما تحرمون من النسب.
Bukhari narrated it in the tafsir (4796), and Muslim in the chapter on breastfeeding (1445), both by way of Ibn Shihab Zuhri, who said, Urwa bin Zubayr told me that Ayesha said, and then he mentioned it. The wording given here is Bukhari's, and Muslim's wording is similar. There are other hadiths on this subject, and they are mentioned in the tafsir of Surah Nur.