Al-Qiyaas linguistically means ‘At-Taqdeer’ (evaluation, measuring). It is said that I did Qiyaas of a thing with another thing and that I did Qiyaas upon it I.e. I measured it with something else (like it). AlQiyaas is also in according to the Arabic language ‘At-Taswiyah’ (levelling, equalisation, settling).

As for its definition according to the Istilaah (definition terminology)

of the scholars of Usool then it is:

‘Ubaidullah Bin Mas’ood Al-Bukhaari defined it by saying:

It is the extension of the Hukm in respect to the origin to the branch due to a unifying (common) ‘Illah (reasoning).

Ash-Shawkaani in his book ‘Irshaad Al-Fuhool’ defined it as:

It is the extraction of the like of a Hukm that has been mentioned to that which has not been mentioned by way of a shared commonality between them both.

Ibn Qudaamah Al-Hanbaliy in his book ‘Rawdat An-Naazhir’ defined it as:

It is the carrying of the branch upon the origin in respect to a Hukm by way of a shared commonality between them.

Al-Ghazaaliy in his book ‘Al-Mustasfaa’ said when defining AlQiyaas:

It is carrying a known matter (Ma’loom) upon a known matter in respect to establishing a Hukm for them both or negating it from them due to a shared commonality that joins them in respect to affirming a Hukm or a Siffah (description/attribute), or in terms of negating them from them.

Al-‘Allaamah ‘Abdul ‘Aliy Al-Ansaariy defined Al-Qiyaas as:

It is the equalising of that which has been silent upon to that which has been mentioned in the text (as found) in the ‘Illah of the Hukm (ruling).

All of these definitions indicate one single meaning which represents the true reality of Al-Qiyaas. This is that there are Shar’iyah texts from the Qur’aan and the Sunnah which mention the Hukm of a matter or issue and also mention the ‘Illah (reasoning) of this Hukm.

The ‘Illah represents the motive/reasoning (Baa’ith) for the Hukm and the following is an example of this:

The Aayah has requested the leaving of trade at the time of Salaat ulJumu’ah and indicates its prohibition at the time of Salaat ul-Jumu’ah as it represents a ‘Man’un’ (prevention/forbiddance) following an Ibaahah (permissibility)’ whilst the ‘Illah of that is the Ilhaa’a (distraction) from the Jumu’ah prayer.

The Mujtahidoon have made analogy upon the trade to any action that distracts from the Jumu’ah prayer. So they said that renting or leasing at the time of Jumu’ah is Haraam because it also distracts from the prayer and similarly practising sport or attending a lecture and so forth... The reason for that is that these actions and what is similar to them contain the ‘Illah of distraction from the Jumu’ah prayer and as such they have taken the Hukm of trading at the time of the prayer, which is the prohibition that has been mentioned in the Aayah, and applied it to that which the ‘Illah is also present in.

Therefore, if we were to apply the first definition of Qiyaas upon this example we would come to the following conclusion:

Practising sport is prohibited at the time of Salaat ul-Jumu’ah joined to the prohibition of trading at the time of Jumu’ah because each of them distracts from the performance of Salaat ul-Jumu’ah or due to the unifying of sport and trade in respect to the ‘Illah which is distraction from the Jumu’ah prayer.