the estimation is more appropriate. If it is said: "The correct position in the School is that the likes of this is not permissible in hire (ijarah), so how have you permitted it in reward (ju'alah)?" We respond: The difference between them is from several aspects. First, ju'alah tolerates uncertainty (gharar) and is permissible with ignorance of the work and the duration, unlike ijarah. Second, ju'alah is a non-binding contract, so no harm results from entering into it with uncertainty, unlike ijarah, which is a binding contract, so if one enters into it with uncertainty, he is bound by it. Third, in ijarah, if it is stipulated by a duration, the work is binding upon him throughout it, and he is not obligated to work after it. If he combines the stipulation of duration and work, he might perform it before the duration expires. If we say he is bound to work for the remainder of the duration, he has been obligated to more work than what was contracted for. If we say he is not, then part of the duration remains without work. If the duration ends before he completes the work and we force him to complete it, he has been obligated to work beyond the contracted duration. If we say he is not obligated, then he has not performed the contracted work. This is unlike our issue, for the work that entitles one to the reward is work restricted by a duration; if he performs it within that time, he is entitled to the reward and is not obligated to anything else, and if he fails to fulfill it within that time, he is entitled to nothing. Once this is established, only the one who performs the work after the information has reached him is entitled to the reward, because it is compensation earned by work, so one who does not work is not entitled to it, just like the wage in ijarah.

Section: It is permissible to set the reward in ju'alah for a specific individual, saying to him: "If you return my slave, you shall have a dinar." No one else who returns him is entitled to the reward. It is also permissible to make it for a non-specific person, saying: "Whoever returns my slave shall have a dinar." Whoever returns him is entitled to the reward. It is permissible to set for one person a known amount for returning him, and for another person more or less than that. It is also permissible to set one compensation for a specified individual and a different compensation for the rest of the people, because it is permissible for the wage in ijarah to differ while there is equality in the work, so here it is all the more permissible.