Historically, Urf’ has many important functions and plays a vital role in Islamic legislation. The first role of Urf’ is that it interprets the unclear text in Al-Quran and Sunnah. The example of this statement can be seen in Al-Quran (65:7) which mentions that “Let those who possess means pay according to their means.” This Quranic verse did not specified the accurate amount of maintenance that a husband must provide for his wife. Therefore, the Quranic commentators have used Urf’ to determine the exact amount of such maintenance. Besides, Al-Quran (2:33) also states that “…the father of the child shall bear the cost of the mother’s food and clothing on a reasonable basis. No person shall have a burden laid on him greater than he can bear…” Similarly, the Quranic commentators have used Urf’ to determine the exact amount of maintenance provided by father to his children.
Besides, the second role of Urf’ is also used to determine the Shariah legal rulings. The jurist opinion that was formulated according to the prevailing custom is permissible to depart from them if these customs were found changes through the effluxion of time. The example of this statement can be seen in the permissible of online shopping in modern times. According to Hadith, Prophet Muhammad prohibited the sale of non-existing object but allows salam. This Hadith implied that the contract of Istina’ or online shopping is permissible nowadays. Moreover, the third function of Urf is to avoid hardship toward mankind. The example of this statement can be seen in Al-Quran (22:78). In this verse, it states that “…He has chosen you and has not placed upon you difficulty in the religion.” This verse implied that Urf shall be applied to avoid hardship to Muslims.
In the modern era, Urf’ also plays a very important role in the daily life of mankind. The first example is that Urf’ is used to hire the services of a lawyer when someone is unable to do a job by himself. Besides, Urf’ is also used to appoint a lawyer to conclude a business deal through him in modern times. Moreover, Urf’ is used when someone tries to get back other’s belonging that is gone. Under this situation, the person will not be responsible for the loss of those items that are gone. Furthermore, Urf can also practice by Muslims when there is a flood and the master of the house is not in the house. In such situation, a person can raze a wall and excavate the property if those properties are in danger and it should not be deemed as a crime as his deed is a welfare.
Historically, Maslahah Mursalah has many important functions and plays a vital role in Islamic legislation. The first function of Maslahah Mursalah is to fight against the Zakah defaulters which have been embarked upon by Caliph Abu Bakr who was the first caliph of Islam . Historically, to fight against Zakat defaulters is not an example of Maslahah Mursalah. The reason to this statement is that some of the defaulters did not give Zakat through the channel provided by Caliph Abu Bakr but in fact gave Zakat directly to the poor and needy as they refused to accept Caliph Abu Bakr as the leader of Muslim after the passing away of Prophet Muhammad. Thus, the establishment of the Caliphate and the Imamate institutions can be said to be one of the greatest acts of Maslahah Mursalah. As a result of these two institutions, it can be said that the combating of apostasy and the compilation of Quran into a book shows the successes of the caliphacy of Khalif Abu Bakr.
The second function of Maslahah Mursalah is to prevent the Ummah from ills of corruption. This can be seen when the second caliph of Islam, Umar bin Al-Khattab established a policy framework to guide the appointment of governors, agents and military officials in the conquered lands. He adheres to the methods and orders provided by Prophet Muhammad and appoint those who were qualified first, then trustworthy and lastly knowledgeable. The evidence of this statement can be seen in an incident where a man who wanted to be appointed as an agent said that, “O Ameer al-Mu’mineen, he does not know anything about evil.” In response to this, Caliph Umar bin Al-Khattab said to him, “Woe to you, he is more likely to fall into it.” Hence, the man was not appointed. From this incident, it is clear that Caliph Umar bin Al-Khattab did not appoint anyone who requested to be governor. The reason of this is that he opined that he was obligated to select the best and most suitable person to be the leader and if he rejected the best candidate and choose someone else, it will amount to the betrayal of Allah, His messenger and the believers.
In the modern era, Maslahah Mursalah also plays a very important role in the daily life of Malaysian. The first example can be seen when the Malaysia Islamic Finance Center (MIFC) listed a few legislated incentives which include tax deductibility on certain expenses incurred to establish Islamic broking companies, a tax exemption up to 2016 on the management fees received by fund managers for managing Islamic funds, the Employee Provident Fund (EPF) undertaking that provide US$ 2 billion which is equivalent to RM 7 billion in investment mandates to Islamic fund managers and so forth. All these legislated incentives which aimed to promote Islamic Finance and the Islamic economic system is based on usury which is prohibited in the Al-Quran. However, through Maslahah Mursalah, investors, firms and fund managers are able to take advantage of these legislated incentives. As a result, the investments in the finance sector in Malaysia grow rapidly, the job opportunity increased and the wealth of Ummah also increased.