يُشترط أن يكون المال المدفوع مقابل الإجارة معلومًا بالمشاهدة والوصف، حتى يُزال عنه كل جهالة. لأن النبي ﷺ قال: «من استأجر أجيرًا فليُعلمه أجره». ويجوز أن يكون العوض في الإجارة نقدًا أو غير نقد، أو مالًا أو منفعة. وكل ما جاز أن يكون ثمنًا جاز أن يكون عوضًا، سواء كان عينًا أو منفعة، بشرط أن يكون معلومًا؛ فإن كان مجهولًا لم يصح. فلو استُؤجر شخص لحصاد زرع على جزء مما يُحصد أجرةً له، لم يجز لأن الأجرة مجهولة. أما إذا استُؤجر بصاع أو صاعين، فيجوز. ويجوز أن يُستأجر الأجير أيضًا على طعامه وكسوته، أو يُعطى أجرةً مع طعامه وكسوته، لأن ذلك جائز في حالة المرأة التي ترضع الطفل. قال الله تعالى:

It is stipulated that property paid in return for hiring should be known by such witness and description so as to remove any uncertainty about it. Because the Prophet (pbuh) (pbuh) said: “Whosoever hired a person He has to inform Him about his wage.” Recompense for hiring is allowed to be monetary, non-monetary, property or a benefit. Anything that is allowed to be a price is allowed to be a recompense, whether it was a commodity or a benefit, on condition that it is known; but if it was unknown it would be invalid. So if a person was hired to reap a harvest for a part of the reaped harvest as a wage it is not allowed because the wage is unknown. While if He is hired for one Sa’a (a cubic measure) or two, it is allowed. The worker is allowed to be hired also for his food and clothing, or can be given a wage together with his food and clothing, because this is allowed in the case of the woman who suckles the infant. Allah (swt) said:

﴿وَعَلَى الْمَوْلُودِ لَهُ رِزْقُهُنَّ وَكِسْوَتُهُنَّ بِالْمَعْرُوفِ﴾ [البقرۃ: ٢٣٣] فَكَانَ لَهُنَّ رِزْقُهُنَّ وَكِسْوَتُهُنَّ أُجْرَةً عَلَى الرَّضَاعِ. فَإِذَا جَازَ ذَلِكَ فِي حَقِّ الْمُرْضِعَةِ، فَيَجُوزُ فِي غَيْرِهَا؛ لِأَنَّ هَذِهِ الْحَالَاتِ كُلَّهَا تُعَدُّ مِنْ مَسَائِلِ الْإِجَارَةِ.

“The duty of feeding and clothing and nursing mothers in a seemly manner is upon the father of the child” [Al-Baqarah: 233] So they were entitled to their provision and clothing as a wage for suckling. If this was allowed in the case of the nursing mother then it is allowed in other cases because such cases are all considered as questions of hiring.

باختصار، ينبغي أن يُحدَّد الأجر بطريقة تُزيل كل جهالة فيه، حتى يُوفَّى دون نزاع، لأن العقود إنما شُرعت في الأصل لرفع الخصومات بين الناس. ويجب الاتفاق على الأجر قبل البدء في العمل، ويُكره استئجار العامل قبل الاتفاق معه على أجره. وإذا عُقدت الإجارة على عمل، فإن العامل يستحق الأجر بحكم العقد، لكن لا يجب تسليمه إياه حتى يفرغ من العمل. وبعد ذلك ينبغي أن يُدفع إليه فورًا، لقول النبي ﷺ: «ثلاثة أنا خصمهم يوم القيامة: رجل أعطى بي ثم غدر، ورجل باع حرًّا فأكل ثمنه، ورجل استأجر أجيرًا فاستوفى منه ولم يُعطِه أجره» [رواه البخاري عن أبي هريرة]. فإن كان هناك شرط بتأجيل الأجر، أُجِّل إلى الوقت المحدد له. وإن كان الشرط أن يكون الأجر مُقسَّطًا يوميًّا أو شهريًّا أو أقل من ذلك أو أكثر، فإن الوقت المحدد هو ما اتفق عليه الطرفان. وليس من الضروري أن ينتفع المستأجر بالمنفعة كاملة فعلًا، بل يكفي أن يُمكِّن العامل نفسه من أن يُستخدم، فيصير الأجر واجبًا على المستأجر. فإذا استأجر شخص خادمًا خاصًّا ليخدمه في بيته، فجاء الخادم إلى بيته وعرض نفسه للخدمة، فإنه يستحق الأجر بانقضاء المدة التي كان يمكن للمستأجر أن يستخدمه فيها. وإن كانت الإجارة على خدمة لم يستوفها المستأجر كاملة، فإن تمكينه منها، ولو لم يستفدها، يكفي لاستحقاق العامل للأجر، لأن التقصير حينئذ من جهة المستأجر لا من جهة الأجير. لكن بالنسبة للأجير المشترك، إذا استُؤجر للعمل في شيء معين، فإنه إما أن يعمل فيه والشيء تحت يده، كالرسام الذي يرسم في دكانه، والخياط الذي يعمل في دكانه. فلا تنتهي مسؤوليته عن إنجاز العمل حتى يسلّمه إلى المستأجر، ولا يستحق أجرته حتى يسلّمه بعد الفراغ منه. وذلك لأن الشيء المتعاقد عليه تحت يده، ولا يبرأ من المسؤولية حتى يسلّمه إلى المستأجر. وكذلك قد يُتعاقد على أن يكون العمل داخل نطاق المستأجر، كأن يُحضر المستأجر الخياط أو الرسام إلى بيته ليخيط أو يرسم له، فيبرأ الأجير من مسؤولية العمل ويستحق أجرته بعد فراغه منه، لأنه كان تحت سلطة المستأجر، فيكون العمل قد سُلّم حالًا.

In short, the wage should be defined in a manner that removes any ignorance about it, so that it can be duly fulfilled without dispute, because all contracts are originally laid down to remove disputes among people. Before starting the work, the wage has to be agreed upon, and it is disliked (Makruh) to use a worker before agreeing with Him over his wage. If the hiring over a work was contracted, the worker is appropriated the wage by the force of the contract, but it is not obligatory to hand it over to Him until the work is finished. Thereafter, it should be immediately handed over to him, due to the saying of the Prophet (pbuh) (pbuh): “There are three persons of whom I am their opponent on the Day of Judgement: A man who gave (a word) in my name then He deceived, a man who sold a free person and devoured his price, and a man who hired a worker where He received (the work) from Him in full and did not give Him his wage”, narrated by Bukhari from Abu Hurairah. But if there was a condition to delay the wage, then it should be delayed to its fixed time. If the condition states that the wage is in instalments daily, monthly, or less, or more than that, then the fixed time is that which the two parties agreed upon. It is not necessary that the employer actually receives the benefit in full, rather it is enough that the worker makes himself available to be used, so that the wage becomes due from the employer. So, if a person hired a private worker to serve Him in his house, and the worker came to their house and put himself at his disposal, then He deserves the wage by the end of the time period in which He could have been used by the employer. Even though the contract is for a service which may not have been fully received by the employer, enabling the employer to receive it even if He did not, this is enough for the worker to deserve the wage. This is because the shortcoming is from the side of the employer rather than the employee. However, for the common employee, if He was employed to work on a certain thing, then He would either do it while it is kept under his authority, like the painter who paints in his own shop, and the tailor who works in his own shop. So his responsibility to do the work will not finish until He has handed it back to the client, and He does not deserve his wage until He has handed it over after completion. This is because the thing contracted upon is under his authority, and He would not be cleared of responsibility until He hands it over to the client. Likewise, the work may be contracted to be done within the domain of the employer, for example if the employer brought the tailor or the painter to his house to sew or paint for him, then the employee would be cleared of the responsibility of the work and deserve his wage once He had finished it, because He was under the authority of the employer, and thus the work was handed over immediately.