A fatwa is a universally applicable religious law concerning a particular issue that is derived from the four sources of Islamic law (the Qur`an, the sunnah, ijma’ (consensus), and ‘aql (the intellect)) using the methodology of ijtihad (juristic interpretation).
A hukm on the other hand, is a law issued by a qualified mujtahid (jurist) who is the head of an Islamic government. Such a leader, by keeping in mind the general principles of divine law, the Islamic systems[i], and prevailing conditions, issues a hukm (legal ruling) for all people, a specific contingency, or an individual.
From the divine perspective, obedience of both a fatwa and a hukm is obligatory. The only difference in this regard is that a fatwa is only legally binding on the mujtahid who issues it and his muqallid (one who imitates his rulings), while the hukm is binding on all groups or individuals enumerated in the hukm.
[i] For every aspect of human life, Islam has put forth a set of universal institutions. Taken together, these institutions, in all their aspects, form a structure or “system,” which works towards the objectives that are based on Islamic principles. Thus, the “Islamic economic system” is the set of universal institutions applying to the aspects of economics.
When a mujtahid derives a legal ruling concerning a given issue by referring to the sources of Islamic law (the Qur`an, the sunnah, ijma’ (consensus), and ‘aql (the intellect)) using the methodology of ijtihad (juristic interpretation), the ruling which he ascertains is called a fatwa. Thus, a fatwa is a universally applicable religious law concerning a particular issue.[1]
However, when the mujtahid takes into account the general principles of divine law, the specific system in place in his country, and prevailing conditions, and issues a legal ruling for all people, a specific contingency, or an individual, such a ruling is called a hukm. In this way, a hukm, while taking into account general Islamic principles, values, and goals, also looks to the specific conditions of a people. Therefore, such a ruling remains in place as long as those conditions prevail.
From the divine perspective, obedience of both a fatwa and a hukm is obligatory.[2] The only difference in this regard is that a fatwa is only legally binding on the mujtahid who issues it and his muqallid (one who imitates his rulings), while the hukm is binding on all groups or individuals enumerated in the hukm.