The Islamic Personality by Sheikh Taqīuddīn An-Nabahānī

Al-sabab in the jurisprudents terminology is every apparent precise quality, which the auditory evidence shows that it is an indication sign for the existence of the verdict (hukm) not the legislation of it, like making the traverse of the sun from the zenith of the sky a sign that indicates the existence of the prayer in the saying of Allah Ta’ala: (Perform the salaat since the traverse of the sun till the darkness of the night…), 78 surat Al- Israa’, and in the saying of the Messenger of Allah (SAW):

“if the sun traverses from the zenith of the sky, then do pray”, narrated by Al- Bayhaqi. It is not a sign for the obligation (wujoub) of the salaat, and like making the appearance of the crescent of Ramadhan an indication sign for the existence of the fasting of Ramadhan in the saying of Allah Ta’ala: (…so whosoever from among you witnesses the month; must then fast it…), 185 SURAT Al-Baqarah, and His (SAW) saying: " “Do fast for the sight of it (the crescent…)”, narrated by Ahmad, and thus the sabab (cause) is not a reason for obliging the verdict, but an indicator for its existence. And the reality of the sabab is that, it is set by the shari'ah for the shari'ahi verdict, for a wisdom necessitated by that verdict.

So the occurrence of the nisaab (specified amount) is a sabab for the existence of the zakaat, and the shari'ahi agreements are sabab for permitting (ibahah) the utilization or transition of the ownership of the properties, so the (hukm) verdict is the obligation of the zakaat and the occurrence of the nisaab is set by the shari'ah for this hukm to indicate the obligation of its existence. And the ibaha of the disposal or the transition of the property is the hukm, and the agreements are set by the shari'ah for this hukm to indicate it existence. So the asbab (causes) are signs, set by the legislator to inform the mukallaf about the existence of the hukm. So the legislator had legislated the hukm for the mukallaf, and assigned him with it, and set signs that indicate the existence of that hukm. So these signs are the shari'ahi asbaab. So the sabab is a notification and an indicator for the existence of the hukm, it is not a definer of the reality or the quality of the hukm, but it indicates its existence only, because what obliges the hukm is the daleel (evidence ) which included it, and what indicates its existence is the sabab. And this is contrary to the illah, which is the thing for which the hukm was legislated, so the hukm was legislated by it, so it is the inducement, and the reason for its legislation, not the cause of its existence.

So the illah is one of the evidences for the hukm, similar to the text in the legislation of the hukm, it is not a sign for the existence, but an informative sign for the legislation of the hukm, like the distraction from the prayer which is derived from His Ta’ala‘s saying: (O you who believe (Muslims) when it is called for the Salaat (Al-Jumu’ah) on Friday, come to the remembrance of Allah and leave off the business…), 9 Surat Al-Jumu’ah, and His saying: (Then when the Salaat is ended, do disperse through the land…),10 Surat Al-Jumu’ah, so the distraction is the reason for which the hukm is legislated, that is the forbiddance of the trade at the (adthaan) call of the Jumu’ah prayer, therefore it is a illah (reason for the legislation not a sabab, contrary to the (dulouk) traverse of the sun, it is not a illah, because the dthuhr prayer was not legislated for it but the zawal is a sign that the existence of the dthuhr prayer becomes a wajib.