Aisha, (mother of the faithful believers) wanted to buy a slave girl and manumit her, but her masters said that they would sell her only on the condition that her Wala' would be for them. ʿAisha told Messenger of Allah ﷺ of that. He said, "What they stipulate should not hinder you from buying her, as the Wala' is for the manumitted."
أَهْلُهَا نَبِيعُكِهَا عَلَى أَنَّ وَلاَءَهَا لَنَا فَذَكَرَتْ ذَلِكَ لِرَسُولِ اللَّهِ ﷺ فَقَالَ لاَ يَمْنَعُكِ ذَلِكَ فَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ