Bukhari

Hadith Commentary:
(1)
The literal meaning of "wala" is help and love. In the legal (shar‘i) terminology, it refers to the relationship that is established between a slave and the one who emancipates him. Its benefit is that if the freed slave dies and has no blood relative as an heir, then his estate goes to the one who set him free.

(2)
The husband of Hazrat Barirah radi Allahu anha was Mughith, who at the time of Hazrat Barirah’s radi Allahu anha emancipation was a slave. The Messenger of Allah sallallahu alayhi wa sallam gave Hazrat Barirah radi Allahu anha the choice: if she wished, she could remain in the marriage bond with her husband Mughith, or if she wished, she could separate from him. Thus, she chose separation. The fact that the Messenger of Allah sallallahu alayhi wa sallam gave Hazrat Barirah radi Allahu anha this choice is evidence that Mughith was a slave.

(3)
In any case, the estate of a freed slave goes to the one who emancipated him, and if a foundling (a child found on the road with unknown parentage) dies, his estate is deposited in the public treasury (bayt al-mal), because he is free. If he were a slave, then his estate would go to the person who picked him up. Imam Bukhari rahimahullah, through the presented hadith, has also explained the ruling regarding the inheritance of a foundling (laqit). And Allah knows best.

Hadith Commentary:
Many benefits are derived from the hadith of Barirah (radi Allahu anha).
Some of the later scholars have enumerated them up to four hundred, though most of these are excessive and strained.
Some benefits have also been mentioned by Hafiz (rahimahullah) in Fath al-Bari.
These can be consulted there.

Hadith Commentary:
(1)
Imam Bukhari rahimahullah established a chapter in the Book of Conditions (Kitab al-Shurut) with these words:
(Bab al-Mukatab, wa ma la yahillu min al-shurut allati tukhalifu Kitab Allah)
“Such conditions are not permissible which are contrary to the Book of Allah.”
(Sahih al-Bukhari, al-Shurut, Chapter: 17)
Hafiz Ibn Hajar rahimahullah states:
Imam Bukhari rahimahullah, through this chapter heading, has explained the interpretation of “laysa fi Kitab Allah” (“not in the Book of Allah”), and the ruling is general—whether it is established by a text or derived from it. However, that ruling should not be one which is contrary to the Book of Allah.
(Fath al-Bari: 5/433)

(2)
It should be noted that Imam Bukhari rahimahullah derived numerous rulings from the hadith of Barirah; most of these rulings have been mentioned by Hafiz Ibn Hajar rahimahullah.
These issues and categories can be seen in Fath al-Bari.
And Allah knows best.

Hadith Commentary:
(1)
From this hadith, it is understood that if, during a transaction of buying and selling, an unlawful condition is stipulated, then the condition is invalid but the sale itself is valid.

There is a difficulty in this hadith: that the purchase of Barirah (radi Allahu anha) by Aisha (radi Allahu anha), the owners of Barirah (radi Allahu anha) stipulating the condition of wala’ (right of inheritance/loyalty), the sale becoming invalid due to this condition, misleading the sellers, stipulating a condition for them which is neither valid for them nor do they gain anything from it, and in such circumstances, the Messenger of Allah (sallallahu alayhi wa sallam) permitting the purchase—all these matters are causes for difficulty.

Some scholars, due to these difficulties, have rejected this hadith, but according to the majority of scholars, this hadith is authentic.

Some have interpreted this stipulation to mean that the condition was imposed upon them that the wala’ would not be theirs.

Some have said that they were informed of the ruling regarding wala’, that the wala’ belongs to the one who emancipates.

Some have interpreted this condition as being for the purpose of reprimand and rebuke, because when the owners of Barirah (radi Allahu anha) insisted on the condition of wala’ and opposed the command of the Messenger of Allah (sallallahu alayhi wa sallam), he said to Aisha (radi Allahu anha):

“Do not pay any attention to this condition, for this condition is invalid and rejected.”

Our inclination is towards this last interpretation.

Wallahu a‘lam.

Benefits and Issues:
➊
The relationship between a master and his slave under his ownership is called "wala’" (allegiance).
Even after the slave is set free, this relationship remains intact.
The one who sets free is called "mawla (mu‘tiq)" (with a kasrah under the letter "ta", meaning the one who frees), and the freed person is called "mawla (mu‘taq)" (with a fatha above the letter "ta", meaning the one who is freed).
And the connection and kinship between them is called "wala’".
This relationship cannot, in any way, be altered, sold, or gifted.

➋
Non-shar‘i (un-Islamic) conditions are completely void.
They hold no validity whatsoever.

Benefit:
"Wala" is the bond and relationship that is established between the emancipator and the freed slave as a result of emancipation. It is evident that relationships and bonds cannot be sold nor can they be given as a gift to anyone. At times, due to this bond, the emancipator also becomes entitled to inherit from the freed slave. For this reason, ignorant people used to sell this relationship, saying: "You take care of the inheritance, just give me such-and-such amount immediately." The Shari'ah has prohibited this coercion, as relationships are not something to be sold or given as a gift.