From Sahih Muslim (Hadith 3778):
A'isha, the wife of Allah's Apostle (ﷺ), reported:Barira came to me and said: 'A'isha, I have entered into contract for securing freedom with my family (who owns me) for nine 'uqiyas (of silver), one 'uqiya every year The rest of the hadith is the same (but with this addition):" This (the problem of the right of inheritance) should not stand in your way. Buy her, and set her free. He said in a hadith: Allah's Messenger (ﷺ) stood up among men, extolled Allah, praised Him, and then said:" for
Reference: Muslim 3778