a hire established as an obligation owed by the worker, it is governed by the same rules as an advance-payment sale involving goods owed as an obligation: the fee must be paid in advance, a deadline fixed, and the work described. ʿAbd al-Wahhāb said: “One of the two countervalues must be furnished immediately: either the remuneration must be paid or receipt of the service must begin.” He means when the work is brief, so as to avoid exchanging one deferred debt for another.
As for a hire personally binding upon the worker, it falls into two categories: first, hiring him for specified work not tied to a particular object; and second, hiring him for specified work tied to a particular object.
The first category—hiring him for specified work not tied to a particular object—is terminated only by the worker’s death. It comprises two types. The first has no inherent endpoint, such as domestic service, tending sheep that are not individually specified, carrying a load that is not individually specified, and similar work. The second has a known endpoint, such as sewing a garment that is not individually specified, grinding a qafīz-measure of wheat that is not individually specified, and similar work.
For the first type, a term must be fixed in days or months for service and labour, while the places and destinations must be named for transport and carriage. If, in transport and carriage, a term in months or days is stipulated alongside the named places and destinations, the contract is invalid and impermissible, because it involves contractual uncertainty and falls within the prohibition of two conditions in a sale, according to the well-known position within the school. It has also been held permissible, based on an interpretation of the discussion in al-Mudawwana concerning riding animals and beasts of burden, and on what appears at the beginning of Ibn al-Qāsim’s transmitted reports in the Book of Task-Based Rewards and Hiring in al-ʿUtbiyya. For the second type, no term may be stipulated, according to the well-known position within the school already mentioned.
As for the second category—hiring him for specified work tied to a particular object—it comprises five types:
(The first) is hiring him to perform work involving a particular object, where the work has no endpoint unless a term is fixed. Examples include hiring him to tend individually specified sheep, or to trade with a specified fund, for a month or a year, and similar arrangements. There is disagreement over the conditions under which such hiring is permissible. One view is that it is permissible only if replacement is stipulated. This is Ibn al-Qāsim’s position and what he transmitted from Mālik, may Allah have mercy on him, in al-Mudawwana and elsewhere. Another view is that it is permissible without stipulating replacement, since replacement is required by the legal ruling itself. This is the position of Sahnūn and Ibn Habīb, and Ashhab’s position in the section entitled Sale and Currency Exchange, among Asbagh’s transmitted reports in the Book of Task-Based Rewards and Hiring. Such is the ruling for this form, except in four