That ʿAisha told him that Barirah came to seek her help in her writing of emancipation (for a certain sum) and that time she had not paid anything of it. ʿAisha said to her, "Go back to your masters, and if they agree that I will pay the amount of your writing of emancipation and get your Wala', I will do so." Barirah informed her masters of that but they refused and said, "If she (i.e. ʿAisha) is seeking Allah's reward, then she can do so, but your Wala' will be for us." ʿAisha mentioned that to Allah's Apostle who said to her, "Buy and manumit (free) her, as the Wala' is for the liberator." Messenger of Allah ﷺ then got up and said, "What about the people who stipulate conditions which are not present in Allah's Laws? Whoever imposes conditions which are not present in Allah's Laws, then those conditions will be invalid, even if he imposed these conditions a hundred times. Allah's conditions (Laws) are the truth and are more solid."  

أَنَّ بَرِيرَةَ جَاءَتْ تَسْتَعِينُهَا فِي كِتَابَتِهَا وَلَمْ تَكُنْ قَضَتْ مِنْ كِتَابَتِهَا شَيْئًا قَالَتْ لَهَا عَائِشَةُ ارْجِعِي إِلَى أَهْلِكِ فَإِنْ أَحَبُّوا أَنْ أَقْضِيَ عَنْكِ كِتَابَتَكِ وَيَكُونَ وَلاَؤُكِ لِي فَعَلْتُ فَذَكَرَتْ ذَلِكَ بَرِيرَةُ لأَهْلِهَا فَأَبَوْا وَقَالُوا إِنْ شَاءَتْ أَنْ تَحْتَسِبَ عَلَيْكِ فَلْتَفْعَلْ وَيَكُونَ وَلاَؤُكِ لَنَا فَذَكَرَتْ ذَلِكَ لِرَسُولِ اللَّهِ ﷺ فَقَالَ لَهَا رَسُولُ اللَّهِ ﷺ ابْتَاعِي فَأَعْتِقِي فَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ قَالَ ثُمَّ قَامَ رَسُولُ اللَّهِ ﷺ فَقَالَ مَا بَالُ أُنَاسٍ يَشْتَرِطُونَ شُرُوطًا لَيْسَتْ فِي كِتَابِ اللَّهِ مَنِ اشْتَرَطَ شَرْطًا لَيْسَ فِي كِتَابِ اللَّهِ فَلَيْسَ لَهُ وَإِنْ شَرَطَ مِائَةَ مَرَّةٍ شَرْطُ اللَّهِ أَحَقُّ وَأَوْثَقُ  

Aisha wanted to buy a slave-girl in order to manumit her. The girl's masters stipulated that her Wala' would be for them. Messenger of Allah ﷺ said (to ʿAisha), "What they stipulate should not stop you, for the Wala' is for the liberator."  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ يَمْنَعُكِ ذَلِكِ فَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ