Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "Give the fixed shares to those entitled to them; whatever remains is for the nearest male."
(b) So he informed us that the one who takes as 'asabah is only a man, except where another Sunnah has made a specific exception; and regarding Aishah's freeing of Barirah, he (peace and blessings be upon him) said: "Wala' belongs only to the one who frees." This hadith shows that she inherits by wala'.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21510
Sayyiduna Ali, Sayyiduna Abdullah and Sayyiduna Zayd bin Thabit (may Allah be pleased with them) used to assign the wala' to the senior among the 'asabah, and among women only those inherited the wala' who had done the freeing, or (the wala' of) one freed by someone they had freed.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21511
Muhammad bin Sirin (may Allah have mercy on him) said: Women do not inherit anything of the wala, except of the one with whom they made a contract of manumission (mukatabah) or whom they freed.
(b) Sufyan al-Thawri (may Allah have mercy on him) said: Women do not inherit anything at all of the wala, except that they make a contract of manumission, or free (a slave), or the one whom they freed frees (another), or the one whom they freed draws (another's) wala.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21514
Ibn Abi al-Zinad said that the jurists of Madinah used to say: A woman does not inherit the wala of any of her near relatives; she inherits only the wala of the one whom she herself freed, or of the one who made a contract of manumission with her and so gained his freedom, or the wala of the freedman of the one whom she freed.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21515