The Sabab from the angle of the capability of the Mukallaf is of two kinds:

1 – The Sabab which is from the actions of the Mukallaf and within his capability to do.

An example of that is:

The Safar (travel) that the Shar’a has specified which is the Sabab for the permissibility of breaking the fast in Ramadhaan.

2 – The Sabab which is not from the actions of the Mukallaf and not within his capability to do.

Examples of that include:

The passing of the sun from the middle of the sky as being the Sabab for the presence of the Zhohr prayer.

And death being the Sabab for the transference of property from the one being inherited from to the inheritor.

1 – The ‘Illah represents the Baa’ith (motivator/reason) for the Hukm i.e. it is that for the purpose or reason of which the Hukm came about. This is like the ‘Ilhaa’ (distraction) from the Jumu’ah prayer which is the ‘Illah for the Tahreem (prohibition) of trading at its time.

That is whilst the Sabab is a sign or indicator (Amaarah) for the presence of the Hukm. Therefore, the passing of the sun (Zawaal) from the middle of the sky is the Sabab (cause) for the presence of the Zhohr prayer. It wasn’t for the sake or purpose of Zawaal (passing of the sun) that the Hukm came into being.

2 – If the same ‘Illah (reasoning) is found within two matters where the Hukm for one of them is mentioned or found in the texts whilst the other does not have a Hukm mentioned for it, then analogy is made for the second matter upon the first and then provided with the same Hukm (ruling). So for example, trading contains distraction from the Jumu’ah prayer at the time of its call and so analogy is made upon it to swimming or any other matter that distracts or diverts somebody from the Salaah. These matters then take the Hukm of trading at the time of prayer which is Tahreem (prohibition). This is whilst the existence of the Sabab does not dictate Qiyaas (analogy). So the Zawaal of the sun from the middle of the sky is the Sabab for the presence of the Zhohr prayer. Then if another matter takes place at the time of Salaat Uzh-Zhohr like trading for example, the trading would not take the Hukm of the obligation of the Zhohr prayer. That is because the Sabab is not an incentive or reason for Qiyaas (analogy) to then be made upon unlike the ‘Illah.

3 – The Sabab precedes the Hukm: So the sighting of the new moon of Ramadhaan is the Sabab for fasting and that Sabab precedes the Musabbab (caused matter) which is the fasting of Ramadhaan.

This is whilst the ‘Illah accompanies the Hukm and does not precede it. So the distraction from the Jumu’ah prayer which is the ‘Illah for the prohibition of conducting trade at the time of the prayer accompanies the Hukm (ruling) and does not precede it.