Sunan an-Nasa'i, Book 26, Hadith 121 (In-Book) ⓘ

It was narrated that 'Aishah said: "Aflah, the brother of Abu Al-Qu'ais, who was my paternal uncle through breast-feeding, used to ask permission to enter upon me, and I refused to let him in until the Messenger of Allah came, and I told him about that. He said: 'Let him in, for he is your paternal uncle.'" 'Aishah said: "That was after the (Verse of) Hijab had been revealed."

أَخْبَرَنَا هَارُونُ بْنُ عَبْدِ اللَّهِ، أَنْبَأَنَا مَعْنٌ، قَالَ حَدَّثَنَا مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، قَالَتْ كَانَ أَفْلَحُ أَخُو أَبِي الْقُعَيْسِ يَسْتَأْذِنُ عَلَىَّ وَهُوَ عَمِّي مِنَ الرَّضَاعَةِ فَأَبَيْتُ أَنْ آذَنَ لَهُ حَتَّى جَاءَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَأَخْبَرْتُهُ فَقَالَ ‏ "‏ ائْذَنِي لَهُ فَإِنَّهُ عَمُّكِ ‏" ‏ ‏.‏ قَالَتْ عَائِشَةُ وَذَلِكَ بَعْدَ أَنْ نَزَلَ الْحِجَابُ ‏.‏