al-Zuhri ابن شهاب الزهري‎, محمد بن مسلم · The Chapters on Manumission (of Slaves)

“A man among us promised freedom to a slave after his death, and he did not have any property other than him (this slave). So the Prophet (ﷺ) sold him, and Ibn (Nahham), a man from Banu 'Adi, bought him.”

“The Mudabbar is part of the one third of the estate.”

the warrior in the path of Allah, the mukatab seeking to fulfill (his manumission debt), and the one getting married seeking chastity."

“If anyone of you (women) has a Mukatab, and he has enough (wealth) to pay off (his contact of manumission), she must veil herself from him.”

I said to Ka'b bin Murrah, tell us a Hadith from the Messenger of Allah (ﷺ), but be careful. He said: I heard the Messenger of Allah (ﷺ) say: “Whoever frees a Muslim man, he will be his ransom from the Fire; each of his bones will suffice (as a ransom) for each of his bones. Whoever frees two Muslim women, they will be his ransom from the Fire; each of their two bones will suffice (as a ransom) for…

“I said: 'O Messenger of Allah (ﷺ), which slave is best?' He said: ‘The one who is most precious to his master and most valuable in price.' ”