Urwah bin al-Zubayr (may Allah have mercy on him) said that Sayyidah Aishah (may Allah be pleased with her) said: Aflah (the brother of Abu al-Qu'ays) asked my permission (to enter) after the command of hijab had been revealed. I said to him: I will not give you permission until I ask permission of the Messenger of Allah (peace and blessings be upon him), for the brother of Abu al-Qu'ays did not suckle me; rather, the wife of Abu al-Qu'ays suckled me. She said: The Messenger of Allah (peace and blessings be upon him) came in to me, and I said: O Messenger of Allah, Aflah (the brother of Abu al-Qu'ays) asked my permission to enter, and I refused to give him permission until I asked you about it. The Messenger of Allah (peace and blessings be upon him) said to me: "What prevents you from giving permission to your uncle?" I said: O Messenger of Allah (peace and blessings be upon him), the man did not suckle me; rather, his wife suckled me. Sayyidah Aishah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "Give him permission, for he is your uncle, may your hands be covered in dust."
Urwah (may Allah have mercy on him) said: Because of this, Sayyidah Aishah (may Allah be pleased with her) used to say: "Treat as unlawful through suckling (all) that you treat as unlawful through lineage."
These are the words of the hadith of Shu'ayb bin Abi Hamzah. In the narration of Uqayl it says (after the command of hijab was revealed): I said: By Allah, I will not give him permission until I ask the Messenger of Allah (peace and blessings be upon him), and the rest (of the narration) is similar. Bukhari narrated it in his Sahih from Yahya bin Bukayr and Abu al-Yaman.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الرضاع / 15607