Is usury (riba) applicable between a mukatab and his master in exchange transactions?
General Chapter
Al-Mughni
Book of Mukātaba (Contractual Manumission)
Primary text
A transaction between the slave and his master involving selling a dirham for two dirhams, like transactions between non-relatives, is not permitted. Ibn Abi Musa held that there is no usury between them, viewing the slave, according to the apparent meaning of the text, as not subject to riba in dealings with the master, similar to the permissibility of the master accepting early payment or remitting part of the manumission price, and the master's right to sexual relations with a female contracted slave if stipulated, resulting in her becoming an umm walad if she conceives.
Supporting text
The view held by Al-Kharqi is that the master and his mukatab are treated as non-relatives in commercial dealings, evidenced by each having the right of preemption against the other, and neither having the right to dispose of the other's property, although the master has a right over the mukatab's possessions due to the contingency of the mukatab failing and the property reverting. This does not preclude the application of usury between them, analogous to a father and his son. Consequently, under this opinion, unequal exchange in items where disparity is forbidden among non-relatives, and delayed exchange in items where delay is forbidden among non-relatives, are not permissible between them.