Usool ul-Fiqh has two main objectives:

1) To verify that the Adillah Al-Ijmaaliyah are definitely (Qat’an) from the Wahi (divinely inspired revelation). This means that is essential for these Adillah (evidences) like the Qur’aan, Ijmaa’ and others to be definitely proven to be from Allah. This is because Allah Ta’Aalaa says:

And He Ta’Aalaa says:

respect to whether it is from Allah or not? And for the Masdar (source) to be considered as a Hujjah (valid proof) then it is necessary for the Daleel Al-Qat’iy (definite evidence) which is the ‘Burhaan Al'Qaat’i’ (decisive proof) to establish its consideration as a Hujjah. This is so that the Muslim is convinced and assured that what he is undertaking in terms of actions are in line with the commands of Allah and what He Ta’Aalaa has forbidden.

2) The application of the Qawaa’id of Usool ul-Fiqh upon the detailed Shar’iyah evidences like the Aayaat, the Ahaadeeth and others is for the purpose of arriving at the practical Ahkaam Ash'Shar’iyah that bind the Muslims in their lives so that they adhere to them when undertaking actions. This objective is of the most noble of objectives and that is because Allah Ta’Aalaa created the human and revealed the Sharee’ah to him so that he abides by its Ahkaam in his life of the Dunyaa. He will then be held to account upon that on the Day of Judgement where it will either be Jannah (paradise) or the Naar (fire). Allah Ta’Aalaa said:

And He Ta’Aalaa said:

The following is a practical example in respect to the manner of how to apply the Qawaa’id (principles) of Usool ul-Fiqh upon the detailed Shar’iyah evidences, in order to deduce or extract a practical Shar’iy Hukm (ruling):

Allah Ta’Aalaa states:

And Allah Ta’Aalaa said:

1) If we were to take the Qaa’idah (principle) from the Qawaa’id of Usool: ‘The later Nass (text) abrogates the former Nass (text)’ then the Aayah from Soorah At-Talaaq would be abrogating the Aayah from Soorah Al-Baqarah because it was revealed after it. The period of waiting (‘Iddah) of the pregnant woman whose husband had died would be completed by her giving birth in accordance to the Qawl of Allah Ta’Aalaa:

2) There are scholars of Usool who say that the Naskh (abrogation) requires another Daleel that indicates the abrogation of an Aayah by another, in addition to the issue of one being advanced and the other being delayed (i.e. in terms of the time of revelation). These scholars combined these two Daleels that appeared to be contradictory and said:

The one whose husband dies whilst she is pregnant could perceive a contradiction in respect to the length of time of her ‘Iddah (waiting period) and particularly if she was to give birth after her husband’s passing in less than four months and ten days. As such they presented the following solution:

It is possible to reconcile between the two evidences in the following way. The pregnant woman whose husband has passed away waits for the longer of the two time periods. If she gives birth before four months and ten days from the date of his death, then she waits until the four months and ten days is completed. And if that time comes to an end before she has given birth then she waits until she has given birth. And this Tawfeeq (reconciliation) between the two evidences represents an application of the Qaa’idah (principle) in Usool ul-Fiqh that states: ‘Working with the two evidences is better (or more appropriate) than neglecting one of them’.