Sunan Ibn Majah 1945
It was narrated from 'Aishah:
that the Prophet entered upon her and there was a man with her. He said: “Who is this? She said: “This is my brother.” He said: “Look at whom you allow to enter upon you, because the breastfeeding (that makes a person Mahram) is that which satisfies hunger.”
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ أَشْعَثَ بْنِ أَبِي الشَّعْثَاءِ، عَنْ أَبِيهِ، عَنْ مَسْرُوقٍ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ دَخَلَ عَلَيْهَا وَعِنْدَهَا رَجُلٌ فَقَالَ ‏"‏ مَنْ هَذَا ‏"‏ ‏.‏ قَالَتْ هَذَا أَخِي ‏.‏ قَالَ ‏"‏ انْظُرُوا مَنْ تُدْخِلْنَ عَلَيْكُنَّ فَإِنَّ الرَّضَاعَةَ مِنَ الْمَجَاعَةِ ‏"‏ ‏.‏