When Aisha intended to buy Barira, she said to the Prophet, "Barira's masters stipulated that they will have the Wala." The Prophet ﷺ said (to Aisha), "Buy her, as the Wala is for the one who manumits."  

لِلنَّبِيِّ ﷺ إِنَّهُمْ يَشْتَرِطُونَ الْوَلاَءَ فَقَالَ النَّبِيُّ ﷺ اشْتَرِيهَا فَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ  

Messenger of Allah ﷺ said, "The wala is for the one who gives the silver (pays the price) and does the favor (of manumission after paying the price).  

قَالَ رَسُولُ اللَّهِ ﷺ الْوَلاَءُ لِمَنْ أَعْطَى الْوَرِقَ وَوَلِيَ النِّعْمَةَ