Sunan Ibn Majah Book 19, Hadith 8

“Any slave who has made a contract to buy his freedom for one hundread Uqiyyah and pays it all except ten Uqiyyah; he is still a slave.” (One Uqiyyah is equal to 40 Dirham.)

Previous Hadith

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

Sunan Ibn Majah Book 19, Hadith 7
Next Hadith

“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.”

Sunan Ibn Majah Book 19, Hadith 9