学者们已经提出证据来说明"尔夫"（Al-'Urf，习惯惯例）的重要性，并且依据前代学者的观点，认为它是具有法律效力的（Shar'an），这些前代学者包括：

The ‘Ulamaa have presented evidence in respect to the importance of Al-‘Urf and they considered it to be Shar’an (legitimate) based upon the views of the previous ‘Ulamaa including:

1 —— 伊玛目马立克（Al-Imaam Maalik）在许多教法裁决上，依据的是麦地那人的实际做法，也就是麦地那居民的习俗（'Urf）与惯例。

1 – Al-Imaam Maalik who built (or based) a lot of his Ahkaam upon the actions of the people of Al-Madinah i.e. upon the customs of Ahl-ul-Madinah and their ‘Urf.

2 – 阿布·哈尼法及其学生（追随者）在某些沙里亚教法条例上存在分歧，其依据是各地习俗（A'araaf）的不同。

2 – Abu Haneefah and his students (followers) differed in respect to some of the Ahkaam Ash-Shar’iyah based upon the difference in their A’araaf (customs).

3 – 伊玛目沙斐仪在前往埃及后改变了一些他在巴格达时所持的教法裁定。有人认为这是由于两地习俗（'Urf）的差异所致，也正因如此，他有两个学派：旧学派与新学派。

3 – Al-Imaam Ash-Shaafi’iy changed some Ahkaam after going to Egypt which he had previously held whilst he was in Baghdad. That has been argued to be due to the differences in ‘Urf between the two places and it is for this reason that he has two Madh’habs, the old and the new.