وَحَدَّثَنِي مَالِكٌ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ عَمْرَةَ بِنْتِ عَبْدِ الرَّحْمَنِ، أَنَّ بَرِيرَةَ، جَاءَتْ تَسْتَعِينُ عَائِشَةَ أُمَّ الْمُؤْمِنِينَ فَقَالَتْ عَائِشَةُ إِنْ أَحَبَّ أَهْلُكِ أَنْ أَصُبَّ لَهُمْ ثَمَنَكِ صَبَّةً وَاحِدَةً وَأُعْتِقَكِ فَعَلْتُ ‏.‏ فَذَكَرَتْ ذَلِكَ بَرِيرَةُ لأَهْلِهَا فَقَالُوا لاَ إِلاَّ أَنْ يَكُونَ لَنَا وَلاَؤُكِ ‏.‏ قَالَ يَحْيَى بْنُ سَعِيدٍ فَزَعَمَتْ عَمْرَةُ أَنَّ عَائِشَةَ ذَكَرَتْ ذَلِكَ لِرَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ اشْتَرِيهَا وَأَعْتِقِيهَا فَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ ‏"‏ ‏.‏

Malik related to me from Yahya ibn Said from Amra bint Abd ar-Rahman that Barira came asking the help of A'isha, umm al-muminin.A'isha said, "If your masters agree that I pay them your price in onelump sum and set you free I will do it." Barira mentioned that to hermasters and they said, "No, not unless your wala' is ours." Yahya ibnSaid added that Amra bint Abd ar-Rahman claimed that A'isha mentionedthat to the Messenger of Allah, may Allah bless him and grant himpeace, and the Messenger of Allah, may Allah bless him and grant himpeace said, "Buy her and set her free. The wala' only belongs to theone who sets free." Translation Not Available

Book Ref: Muwatta Imam Malik Book 38 Hadith 1484
Web Ref:  Muwatta Imam Malik Book 38 Hadith 19