Sahih Bukhari
Manumission of Slaves
Volume: 003 / Book Number: 046 / Hadith Number: 738
Narrated 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."