One of the characteristics of the Qur'anic legislation is that commandments and prohibitions are expressed in a variety of forms, which are often open to interpretation and ijtihad. The question as to whether a particular injunction in the Qur’an amounts to a binding command or to a mere recommendation or even permissibility cannot always be determined from the words and sentences of its text. These provisions are five in number and are they briefly defined below:
1 – Obligatory (Wajib or Fard): it is legally defined as what the lawmaker makes binding and obligatory. The ruling on such action is that if carried out, there will be reward and deserves punishment if not carried out.
2 – Commendable or Desirable (Mandub or Mustahab): It is defined as what the lawmaker encouraged but not binding. The ruling of this category of acts is that the doer of such acts will be rewarded but one will not be punished for not doing it.
3 - Forbidden (Haram): It is defined as what the lawmaker made and declared bindingly forbidden. Its ruling is that the doer of such will be punished and the abstainer from it will be rewarded.
4 – Undesirable (Makruh): It is defined as what the lawmaker forbade but not in a binding manner. Its ruling is that the abstainer will be rewarded while the doer will not be punished.
5 - Permissible (Mubah): It is defined as what is generally allowed. Its ruling is that there is neither reward nor punishment for doing or leaving such act.
Broadly speaking, when Allah commands or praises something, or recommends a certain form of conduct, or refers to the positive quality of something, or when it is expressed that Allah loves such-and-such, or when Allah identifies something as a cause of bounty and reward, all such expressions are indicative of the legality (mashru’iyyah) of the conduct in question which partakes in the obligatory and commendable. If the language of the text is inclined on the side of obligation (wujub), such as when there is a definite, demand or a clear emphasis on doing something, the conduct in question is obligatory (wajib), otherwise it is commendable (mandub).
Similarly, when Allah explicitly declares something permissible (Mubah) or grants a permission in respect of doing something, or when it is said that there is 'no blame' or 'no sin' accruing from doing something, or when Allah denies the prohibition of something, or when the believers are reminded of the bounty of Allah in respect of things that are created for their benefit, all such expressions are indicative of permissibility (ibahah) and option (takhyir) in respect of the conduct or the object in question.
Examples are the following sayings of Allah:
ﭣ ﭤ ﭥ ﭦ ﭧ ﭨ ﭩ ﭪ
'And He created for you ships and cattle on which you ride' [al-Zukhruf: 12]
ﯙ ﯚﯛ ﯜ ﯝ ﯞ ﯟ ﯠ ﯡ
'And the cattle, He created them for you; in them for you is warmth, and numerous benefits, and of them you eat' [al-Nahl: 5]
ﭣ ﭤ ﭥ ﭦ ﭧ ﭨ ﭩ ﭪ ﭫ ﭬ ﭭﭮ
'Say (O Muhammad! Peace be upon him): 'Who has forbidden the beautiful gifts of Allah which He has produced for His servants, and the lawful things of sustenance' [al-A’raf: 32]
Whenever Allah demands the avoidance of a certain conduct, or when He denounces a certain act, or identifies it as a cause for punishment, or when a certain conduct is cursed and regarded as the work of Satan, or when its harmful effects are emphasized, or when something is proclaimed unclean, a sin or a deviation (ithm, fisq) - all such expressions are indicative of prohibition which partakes in abomination (karahah). If the language is explicit and emphatic about prohibition, the conduct/object in question becomes haram, otherwise it is reprehensible, or makruh. It is for the mujtahid to determine the precise value of such injunctions in the light of both the language of the text as well as the general objectives and principles of the Shari’ah.
This style of Qur’anic legislation, and the fact that it leaves room for flexibility in the evaluation of its injunctions, is once again in harmony with the timeless validity of its laws. The Qur’an is not specific on the precise value of its injunctions, and it leaves open the possibility that a command in the Qur’an may sometimes imply an obligation, a recommendation or a mere permissibility. The Qur’an does not employ the categories known as the five values (al-ahkam al-khamsah) which the fuqaha' have attempted to specify in juristic manuals. When an act is evaluated as obligatory, it is labeled fard or wajib; when it is absolutely forbidden, it is evaluated as haram. The shades of values, which occur between these two extremes, are primarily religious in character and provide a yardstick, which can be applied to any type of human conduct. Only the two extremes, namely the wajib and haram, are incorporate legal commands and prohibitions. The rest are largely non-legal and non-justiciable in a court of law. The Qur’an thus leaves open the possibility, although not without reservations, of enacting into haram what may have been classified by the fuqaha' of one age as merely reprehensible, or makruh.
Similarly, the recommendable, or mandub, may be elevated into a wajib if this is deemed to be in the interest of the community in a different stage of its experience and development.