Messenger of Allah ﷺ came to me and I told him about the slave-girl (Barirah) Messenger of Allah ﷺ said, "Buy and manumit her, for the Wala is for the one who manumits." In the evening the Prophet ﷺ got up and glorified Allah as He deserved and then said, "Why do some people impose conditions which are not present in Allah's Book (Laws)? Whoever imposes such a condition as is not in Allah's Laws, then that condition is invalid even if he imposes one hundred conditions, for Allah's conditions are more binding and reliable."  

عَائِشَةُ ؓ دَخَلَ عَلَىَّ رَسُولُ اللَّهِ ﷺ فَذَكَرْتُ لَهُ فَقَالَ رَسُولُ اللَّهِ ﷺ اشْتَرِي وَأَعْتِقِي فَإِنَّ الْوَلاَءَ لِمَنْ أَعْتَقَ ثُمَّ قَامَ النَّبِيُّ ﷺ مِنَ الْعَشِيِّ فَأَثْنَى عَلَى اللَّهِ بِمَا هُوَ أَهْلُهُ ثُمَّ قَالَ مَا بَالُ أُنَاسٍ يَشْتَرِطُونَ شُرُوطًا لَيْسَ فِي كِتَابِ اللَّهِ مَنِ اشْتَرَطَ شَرْطًا لَيْسَ فِي كِتَابِ اللَّهِ فَهْوَ بَاطِلٌ وَإِنِ اشْتَرَطَ مِائَةَ شَرْطٍ شَرْطُ اللَّهِ أَحَقُّ وَأَوْثَقُ  

Aisha wanted to buy Barirah and he (the Prophet) went out for the prayer. When he returned, she told him that they (her masters) refused to sell her except on the condition that her Wala' would go to them. The Prophet ﷺ replied, 'The Wala' would go to him who manumits.' " Hammam asked Nafiʿ whether her (Barirah's) husband was a free man or a slave. He replied that he did not know.  

أَنَّ عَائِشَةَ ؓ سَاوَمَتْ بَرِيرَةَ فَخَرَجَ إِلَى الصَّلاَةِ فَلَمَّا جَاءَ قَالَتْ إِنَّهُمْ أَبَوْا أَنْ يَبِيعُوهَا إِلاَّ أَنْ يَشْتَرِطُوا الْوَلاَءَ فَقَالَ النَّبِيُّ ﷺ إِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ قُلْتُ لِنَافِعٍ حُرًّا كَانَ زَوْجُهَا أَوْ عَبْدًا فَقَالَ مَا يُدْرِينِي