Sahih Bukhari: Hadith 2483

I intended to buy Buraira but her masters stipulated that her Wala should be for them. When the Prophet was told about it, he said to me, "Buy and manumit her, as the Wala' is for the liberator." Once Buraira was given some meat, and the Prophet (ﷺ) asked, "What is this?" I said, "It has been given to Buraira in charity." He said, "It is sadaqa for her but a gift for us." Buraira was given the option (to stay with her husband or to part with him). `Abdur-Rahman (a sub-narrator) wondered, "Was her husband a slave or a free man?" Shu`ba (another sub-narrator) said, "I asked `Abdur-Rahman whether her husband was a slave or a free man. He replied that he did not know whether he was a slave or a free man."