Musnad Abu Ya'la al-Mawsili 150:16

Narrated to us Ishaq, narrated to us Jarir, from al-A'mash, from Ibrahim, from al-Aswad, from Aisha, who said: I purchased Barirah in order to free her, but her people stipulated [that they retain] her Wala' (right of inheritance). I mentioned that to the Messenger of Allah, peace and blessings of Allah be upon him, and he said: "Free her, for the Wala' belongs to the one who frees." Her husband was a free man while she was a slave, so the Messenger of Allah, peace and blessings of Allah be upon him, gave her the choice [to remain with him or leave him].