Dear respected Shaykh, assalamu alaikum wa rahmatullahi wa barakatuh. There is a rumor here in Egypt that ‘Aisha (may Allah be pleased with her) breastfed her slave with the permission of the Prophet (peace be upon him). حديث إرضاع عائشة بإذن النبي
Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions. Wa alaikum assalam wa rahmatullahi wa barakatuh. As to what follows: In response to your question, we say: This story is not correct and was not narrated. What was narrated is the story of Salim the servant of Abu Huthaifah. Salim had been adopted by Abu Huthaifah before Allah prohibited adoption with His statement “Call them by [the names of] their fathers; it is more just in the sight of Allah “ [al-Hujurat 33: 5]. When Salim became an adolescent, Abu Huthaifah’s wife came to the Prophet (peace be upon him) and said, “Salim has attained (puberty) as men attain, and he understands what they understand, and he enters our house freely, I, however, perceive that something (rankles) in the heart of Abu Huthaifa, whereupon Allah's Apostle (peace be upon him) said to her: Suckle him and you would become unlawful for him, and (the rankling) which Abu Huthaifa feels in his heart will disappear.” This hadith was transmitted by al-Bukhari (5088) and Muslim (1453) from the hadiths of al-Qasim ibn Muhammad from ‘Aisha. She is the narrator of the hadith and the story did not happen to her. Based on this hadith, a number of scholars held that breastfeeding an adult makes it impermissible for him to marry his foster relatives. This is the opinion of ibn Hazm from the Zahirites and group of jurists. The opinion of the majority of the jurists and hadith scholars is that breastfeeding an adult does not make it impermissible for him to marry his foster relatives. They said that what was narrated in this hadith is a special situation in which the Prophet (peace be upon him) permitted Salim the servant of Abu Huthaifah to be breastfed. These scholars differed on the period in which breastfeeding a child so as to make it impermissible for him to marry his foster relatives is valid.