Kwangilar daukar ma'aikaci tana aiki ne a kan amfanin da yake bayarwa; kuma ana kimanta albashi bisa wannan amfani. Ƙoƙarin kansa ba shi ne ma'aunin albashi ba, kuma ba shi ne ma'aunin amfani ba, in ba haka ba albashin mai aikin dutse zai fi na injiniya girma saboda ƙoƙarin mai aikin dutse ya fi yawa; kuma wannan ya saba wa gaskiyar al'amari. Saboda haka, albashi lada ne na amfani ba na ƙoƙari ba. Bayan haka, albashi yana bambanta yana canzawa gwargwadon irin ma'aikaci, kuma yana canzawa ga ma'aikaci ɗaya gwargwadon bambancin matakin amfani, amma ba gwargwadon bambancin ƙoƙari ba. Kwangilar a cikin dukkan lamuran biyu ta kasance a kan amfanin mai ɗaukar aiki, ba a kan ƙoƙarin ma'aikaci ba. Don haka abin da ke da muhimmanci shi ne sakamako, ko na ma'aikata daban-daban a ayyuka daban-daban, ko na ma'aikata daban-daban a aiki ɗaya; kuma ba a ba ƙoƙari muhimmanci kwata-kwata. Gaskiya ne cewa sakamakon aiki shi ne 'ya'yan ƙoƙari, ko a ayyuka daban-daban, ko a aiki ɗaya da mutane daban-daban suka yi, amma abin da ake nufi shi ne sakamako, ba ƙoƙari kawai ba, ko da yake ana lura da shi wajen kimanta albashi. Saboda haka, idan aka ɗauki mutum don gini, to ya kamata a kimanta albashi ta lokaci ko ta aiki. Idan an kimanta shi ta aiki, to amfanin zai bayyana a fili a wurin ginin, tsawonsa, faɗinsa, kauri da kayan ginin da sauransu. Idan an kimanta aikin ta lokaci, to amfanin aikin yakan ƙaru yayin da lokaci ya ƙaru, kuma yana raguwa yayin da lokaci ya ragu. Don haka bayanin aikin tare da ambaton lokaci shi ne ma'aunin amfani. Idan aka kimanta shi ta lokaci, ba ya kamata ma'aikaci ya yi aiki fiye da ƙarfinsa na yau da kullum, kuma ba a kamata a tilasta masa aiki mai wahala fiye da al'ada ba.

The contract to hire an employee applies on the benefit of the effort He expends; and the wage is evaluated in terms of this benefit. The effort itself is neither the measure of the wage, nor the measure of the benefit, otherwise the wage of the stonemason would be greater than the wage of the engineer because the stonemason’s effort is greater; and this is contrary to the reality. Therefore, the wage is a recompense for the benefit and not for the effort. Besides that, the wage differs and changes according to the type of employee, and it also changes for the same employee according to the difference in the standard of the benefit, but not according to differences in effort. The contract in both cases was over the benefit of the employer, not over the employee’s effort. So what does matter is the result, whether it was of different employees in different works, or of different employees in the same work; and there is no consideration given to the effort at all. It is true that the result of the work is the fruit of the effort, whether it was in different works, or in the same work done by different people, but what is intended is the result, not only the effort, even though this is noticed in the evaluation of the wage. So if a person was hired for building, then the wage should be evaluated by the time or by the work. If it was evaluated by the work, then the benefit will obviously be manifested in the location of the building, its length, width, thickness and the material of the building etc. If the work was evaluated by time, then the benefit of the work usually increases as the time increases, and decreases as the time decreases. Thus the description of the work together with the mentioning of the time is the measure of the benefit. If it is evaluated by time, the person should not work more than his usual capacity, and should not be obliged to do unusually hard labour.