Ayesha wanted to buy Barirah in order to free her, but Barirah's owners insisted on stipulating that they would retain her right of guardianship. Ayesha mentioned this to the Prophet ﷺ, and he said to her, "Buy her, for guardianship belongs only to the one who frees the slave."She said, "Some meat was brought to the Prophet ﷺ, and I said, 'This is what was given to Barirah as charity.'"He replied, "It is charity for her and a gift for us."
أنها أرادت أن تشتري بريرة للعتق وأراد مواليها أن يشترطوا ولاءها فذكرت عائشة للنبي ﷺ فقال لها النبي ﷺ: اشتريها فإنما الولاء لمن أعتق. قالت: وأتي النبي ﷺ بلحم فقلت: هذا ما تصدق به على بريرة فقال: هو لها صدقة ولنا هدية.
Bukhari narrated it in the Book of Zakat (1493), and Muslim in the Book of Zakat (1075), both through the route of Shubah, from Hakam, from Ibrahim, from Aswad, from Ayesha, and I have related it accordingly. The wording is that of Bukhari, while Muslim's wording is abridged, and in it the meat is specified as being beef.