Malik related to me from Nafi from Abdullah ibn Umar that A'isha
umm al-muminin wanted to buy a slave-girl and set her free. Her people
said, "We will sell her to you provided that her wala' is ours." She
mentioned that to the Messenger of Allah, may Allah bless him and
grant him peace, and he said, "Don't let that hinder you, for the
wala' only belongs to the one who sets free."
Muwatta Malik Book 38, Hadith 19