According to Mālik and the scholars who agree with him, the Prophet’s phrase “it is from Allah’s wealth” refers to remitting some portion of the mukātab’s final instalments; doing so, however, is only recommended in Mālik’s school. They also maintain that a master may compel his slave to conclude a kitābah, and both opinions are attributed to Mālik.
By default a kitābah is a deferred contract, payable in specified instalments for a known sum. If a master grants his slave a kitābah without fixing a term, the instalments fall due according to the slave’s capacity to pay. The same rule applies when a man, in his will, orders that his slave be given a kitābah but sets no schedule: the payments are arranged in line with the slave’s ability.
If several slaves are placed under a single kitābah, the contract is effective for each of them in proportion to what he can afford, and—according to Mālik—they are jointly liable for one another. Any slave who cannot meet his share is employed by the others in whatever work he can perform; should he still default and they cover the whole amount, they may reclaim from him what they paid on his behalf as a debt. A fuller discussion of this issue will appear, God willing, in the chapter on partners and on slaves who are granted kitābah together.
A mukātab remains a slave as long as any part of his contract is outstanding: if he pays it all, he is freed; if he fails, he returns to bondage. It is advisable that the document stipulate—binding upon the master—that once the slave has paid all his instalments he is emancipated and joins the ranks of the free Muslims; even if both parties are silent, that consequence is presumed. His walāʾ (patronage right) after payment belongs to his master and, after the master’s death, to the master’s male heirs, like any other manumitted person.
Mālik and his companions allow the contract to include an option period (khiyār) for either party. Their underlying principle is that a kitābah is invalid when its subject matter is unknown, involves uncertainty, or consists of unspecified property. Thus, if the price is set as “a slave” without description, the master is entitled to receive a slave of average quality; but if the contract is based on the slave’s monetary value, it is valid.
When a kitābah is concluded for the delivery of a particular, well-described slave, the mukātab surrenders that slave, the master takes possession, and the mukātab is freed. If the master then discovers in the acquired slave a serious defect, he may seek from the former mukātab an equivalent replacement as a debt owed by him.