Book of Manumission
(1)
It is recommended to set free, or enter into a kitābah contract with, any slave who is able to earn an income.

Manumission is effected by a declaration. Its explicit form is: “I free you,” “I emancipate you,” and the like. Its indirect form (2) includes: “You are my mawla,” “For the sake of Allah,” and similar expressions.

Emancipation is also effected by acquiring ownership of a maḥram relative—such as one’s father, brother, or maternal uncle—or by mutilating one’s slave.

It is valid to suspend emancipation upon a condition: the slave is freed once that condition is met. It may likewise be suspended until the owner’s death, a device known as tadbīr.

Whoever frees a portion of a slave who is solely his property thereby frees the whole slave. If he partially frees a jointly owned slave, the shares of his partners must also be freed, provided he can afford to pay their value.

Section
If a master sells his slave to the slave himself for a price divided into two or more instalments, the sale is valid; once the slave has paid, he is emancipated and his patronage (walāʾ) remains with the seller. Should he fail to pay, he reverts to slavery.

It is permissible to contract kitābah with one’s umm walad, and to sell a slave who is already under kitābah; if the slave pays his purchaser, he is emancipated and his patronage belongs to that purchaser.