عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا أَنَّ بَرِيرَةَ أَتَتْهَا تَسْتَعِينُهَا وَكَانَتْ مُكَاتَبَةً فَقَالَتْ لَهَا عَائِشَةُ رَضِيَ اللَّهُ عَنْهَا أَيَبِيعُكِ أَهْلُكِ فَأَتَتْ أَهْلَهَا فَذَكَرَتْ ذَلِكَ لَهُمْ فَقَالُوا لَا إِلَّا أَنْ تَشْتَرِطَ لَنَا وَلَاءَهَا فَقَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ اشْتَرِيهَا فَأَعْتِقِيهَا فَإِنَّمَا الْوَلَاءُ لِمَنْ أَعْتَقَ
It is narrated from Sayyida Aisha (may Allah be pleased with her) that Sayyida Barirah (may Allah be pleased with her) came to her while she was a mukatab (a slave with a contract for freedom). Sayyida (Aisha) said to her: Will your owners sell you? She went to her owners and told them this. They said: No, we will not do that, except if she stipulates the condition of wala’ (loyalty) for us. When the Prophet Muhammad (peace and blessings be upon him) learned of what they said, he said: Aisha! Buy her and set her free, for wala’ is only for the one who sets free.