Abd al-Rahman bin al-Qasim narrates from his father that Sayyidah Aishah (may Allah be pleased with her) bought Barirah from some people of the Ansar, and they stipulated the wala' for themselves. The Messenger of Allah (peace and blessings be upon him) said: "The wala' belongs to the one who is the patron of the favour (of freeing)." She said: The Messenger of Allah (peace and blessings be upon him) gave Barirah the choice, and her husband was a slave. She gave Sayyidah Aishah (may Allah be pleased with her) some meat as a gift, and the Messenger of Allah (peace and blessings be upon him) said: "Cook this meat for us." Sayyidah Aishah (may Allah be pleased with her) said: This was given in charity to Barirah. He (peace and blessings be upon him) said: "For her it is charity, and for us it is a gift."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14256