Sahih Bukhari | Volume 3 | Hadith Number 738
Narrated by Amra bint 'AbdurRahman
Buraira went to 'Aisha, the mother of the faithful believers to seek her help in her emancipation 'Aisha said to her, "If your masters agree, I will pay them your price in a lump sum and manumit you." Buraira mentioned that offer to her masters but they refused to sell her unless the Wala' was for them. 'Aisha told Allah's Apostle about it. He said, "Buy and manumit her as the Wala' is for the liberator."