Allah (swt) addressed the whole of mankind through the Prophethood of our master Muhammad (saw). He (swt) said:
“Say (O Muhammad (saw)): “O mankind! Verily I am sent to you all as the Messenger of Allah…”’ [TMQ 7:158]
And He (swt) said:
“O mankind! Verily, there has come to you a convincing proof (Muhammad [saw]) from your Lord” [TMQ 4:174]
And He (swt) said:
“O mankind! Verily, there has come to you the Messenger (Muhammad [saw]) with the truth from your Lord.” [TMQ 4:170]
And He (swt) addressed the people and the Muslims with the Ahkam of Islam. He (swt) said:
“O mankind! Fear your Lord and be dutiful to Him! Verily, the earthquake of the Hour (of judgment) is a terrible thing.” [TMQ 22:1]
He (swt) said:
“O mankind! Be dutiful to your Lord, Who created you from a single person...” [TMQ 4:1]
He (swt) said:
“O you who believe! Fight those of the disbelievers who are close to you, and let them find harshness in you…” [TMQ 9:123]
And He (swt) said:
“O you who believe! Approach not As-Salat (the prayer) when you are in a drunken state.” [TMQ 4:43]
And He (swt) said:
“O you who believe! When you go (to fight) in the Cause of Allah, verify (the truth)...” [TMQ 4:94]
And He (swt) said:
“O you who believe! Stand out firmly for justice, as witnesses to Allah, even though it be against yourselves...” [4:135]
From these verses and others similar we understand that Allah (swt) has addressed humanity directly. Therefore for the one who has heard the address of the Legislator, Allah (swt) - it becomes incumbent on him to believe in it and understand it. It also becomes incumbent on him to act upon it, because it is Hukm Shar'ai (Shari'ah rule). So in principle a Muslim should understand the Hukm (rule) of Allah from the speech of the Legislator directly. This is because the speech has been directed at all people by the Legislator and not only at the Mujtahidin or the 'Ulama but all the Mukallafin (those who are legally responsible). Thus it became an obligation on the Mukallafin to understand this speech so as to be able to act upon it, since it is impossible to act upon the speech without comprehending it. Therefore, the inference (Istinbat) of Allah's Hukm became Fard on all the Mukallifin i.e. Ijtihad became Fard on all the Mukallafin (legally responsible). Consequently, the basis of a Mukallaf (legally responsible) should be that he adopts the Hukm of Allah himself from the speech of the Legislator because he has been addressed by this speech.
However, the reality of the Mukallifin (legally responsible) is that there is a disparity in their understanding and comprehension and in their aptitude for learning. They also differ in terms of knowledge and ignorance. Therefore, it is impossible for all of them to deduce Shar’ai rules from the evidences i.e. it is impossible for all Mukallafin to be Mujtahidin. Since the objective is to understand the speech and act upon it then the understanding of the speech i.e. Ijtihad is Fard on all the Mukallafin (legally responsible). However since it is impossible for all Mukallafin to understand the address for themselves due to the disparity of their understanding and the disparity in learning, then the obligation of Ijtihad becomes one of sufficiency ('ala al-Kifaya). If some undertake it the rest are absolved of the sin. Therefore, it became obligatory on those Muslims legally responsible that there should be Mujtahidin amongst them who would derive the Shar’ai rules. There is a similarity in this respect to other sciences, not everyone can become a doctor, physasist or chemist due to the disparity of people’s aptitude for learning.
The reality of the Mukallafin and the Hukm Shar'ai means that there would be two categories amongst the Muslims: the Mujtahidin and Muqallidin. This is because the one who adopts the Hukm himself directly from the evidences is a Mujtahid, and the one who questions the Mujtahid about a Hukm Shar'ai is a Muqallid; irrespective of whether or not the questioner asked about the Hukm to learn and act upon it, to learn and teach it to others or just to learn it. The Muqallid is considered as one when he asks someone who is not a Mujtahid but knows the Hukm Shar'ai and is able to tell others, whether the one who was asked is knowledgeable or just a layman. Thus, they are all followers (Muqallid) of others in this Hukm even if they do not know the one who deduced the Hukm, because the Mukallaf is required to adopt the Hukm Shar'ai and not follow any particular person. Being a Muqallid means he has adopted a Hukm Shar’ai, which he did not deduce himself. It does not mean he followed a particular person, since the subject matter is the Hukm Shar’ai and not the person. The difference between the Muqallid and the Mujtahid is that the Mujtahid deduces the Hukm Shar’ai from the Shari'ah evidence himself and the Muqallid is the one who adopts the Hukm Shar’ai irrespective of whether or not he knew the one who derived it, as long as he trusts the Hukm to be a Shari’ah rule. It is not a permissible Taqleed to adopt the opinion of any person as a personal opinion or the opinion of such and such scholar, thinker or philosopher without it being derived from the Islamic evidences. None of this is legitimate Taqleed. It is tantamount to adopting something other than Islam and this is prohibited by the Shari'ah. Also, Allah has ordered us to adopt from the Messenger Muhammad (saw) and not from anybody else whoever he may be. He (swt) said:
“And whatsoever the Messenger (Muhammad [saw]) gives you, take it, and whatsoever he forbids you, abstain (from it).” [TMQ59:7]
A prohibition has been mentioned with regards to adopting an opinion originating from the peoples own minds without being based on the Islamic evidences. In the Hadith in Sahih of Bukhari, on the authority of 'Urwa b. al-Zubayr who said: 'Abd Allah b. 'Amr b. al-'As overcame us with proof. I heard him say: “Allah will not deprive you of knowledge after he has given it to you, but it will be taken away through the death of the learned men (Ulema’a) with their knowledge. There will remain ignorant people who, when consulted, will give verdicts according to their opinions whereby they will mislead others and themselves go astray.” i.e. they give Fatwas according to their own opinions which are not derived from the Islamic evidences. The opinion that has been deduced from the Islamic evidences is not considered as an opinion originating from the one who deduced it, on the contrary it is considered as a Hukm Shar’ai. As for what is regarded as mere opinion, it is just hearsay which emanates from a person. That is why the Messenger (saw) called it a Bid'aa (innovation). In the authentic Hadith the Prophet (saw) said: “The best speech is the Book of Allah and the best guidance is the guidance of Muhammad (saw). And the evil matters are the newly invented issues and every Bida’a (innovation) is a misguidance.” The 'newly invented issues' are the Bida’a (innovations), they are whatever contradicts the Kitab, Sunnah or Ijma'a in terms of the Ahkam whether by action or speech.
Thus the Taqleed allowed by Shari’ah is for the person unable to deduce Hukm Shar’ai themselves to ask the scholar about the particular Hukm Shar’ai so as to learn and adopt it. To summarise, it is allowed for anybody unaware of a Hukm Shar’ai to ask one who does know the Hukm so he may learn and take it. The subject and evidences for the permissibility of Taqleed are elaborated further in the section concerning Taqleed.
The fact that Ijtihad is an obligation of sufficiency (farD kifaayah), means that no age should be devoid of the presence of a mujtahid, otherwise the Muslims will be sinful.
This has been mentioned by numberous ulema in the past including Sadr al-Shariah who said:
If one or more mujtahid is present then the sin is removed from the Muslims of that age and this is proven from two angles:
Firstly: The texts of the Islamic Sharee’ah requires the Muslims to undertake ijtihad because these texts did not come in an elaborate manner. Even the ones that did come in detail regarding some matters did not cover all the details with a definite text. For example, the ayat of inheritance have come in a detailed manner. However in terms of partial rules they still require scrutiny and deduction such as the issue of Kalaalah and Hajab. The Mujtahidun take the view that the child (Walad) whether male or female, takes precedence in inheritance over the brothers of the deceased because the word ‘Walad' (child) refers to children of both sexes. Despite this Ibn 'Abbas holds the view that the girl does not inherit because the word 'Walad' refers to a male only. This shows that even some texts that treat in detail have come as ambivalent (Mujmal), and understanding and deducing a Hukm from them requires Ijtihad.
This is from the angle of the texts.
Secondly: the newly occurring incidents of life are continuous and so if effort is not expended to deduce the rules relating to them, then it will not be possible apply the Sharee’ah rules on them, knowing that there are numerous texts obliging the application of the Sharee’ah rule on every issue:
He (swt) said: “And so judge (you o Muhammad [saw]) between them by what Allah has revealed.” [TMQ 5:49]
He (swt) said: “But no, by your Lord, they can have no Faith, until they make you (O Muhammad [saw]) judge in all their disputes between them, and find in themselves no resistance against your decisions, and accept (them) with full submission.” [TMQ 4:65]
He (swt) said: “And We have sent down to you the Book (the Qur’an) as an exposition to everything.” [TMQ 16:89]
Thus, ijtihad is fard on those who have the ability in every age i.e. it is a farD kifayah if some have already performed it the rest are absolved of the obligation. This is from the angle whatever is necessary to fulfill a waajib is itself a wajib. Ijtihad is waajib because we cannot refer to what Allah ahs revealed in every issue without ijtihad.
Thus, Islam has encouraged ijtihad by giving the one who gets an ijtihad right two rewards and the one gets it wrong he gets one reward. The Muslims practiced ijtihad from the beginning of Islam. The Sahabah had many ijtihads and their differences in certain issues are well known. They used to deduce rules according to their own ability because they were proficient in the language, they lived which the Qur’an was being revealed. And they learnt directly from the Messenger of Allah (saw).
Then they were succeeded in the following ages by people from whom many mujtahideen emerged such as the Imaams of the mazhabs and their students.
The ages of Islam continued to flourish until the weakness in the ijtihad creped in and its was banned and taqleed became widespread. And the deduced rules of Allah could not keep up with the new emerging issues.
Ijtihad must continue so that there are able mujtihadeen in the Ummah and Islam can lead the world in solving their problems and bring them out from the darkness into light.
The Messenger (saw) gave us the glad tidings that this goodness will not stop and that in the last ages there will from this Ummah those who will work to apply the laws of Allah on the earth and make ijtihad to keep Islam the highest. He (saw) said: “There is will always be a group from my Ummah who will remain in the Haqq (truth) until the Decree of Allah comes and Dajjal appears.”
To say that the doors of Ijtihad are closed is completely incorrect, this was a serious error that some ulema mistakenly called for in history and clearly contradicts the Shari’ah. The Shari’ah texts exist today as they existed in the past, therefore Ijtihad is not only possible, it is necessary and a Fard ul Kifaya (duty of sufficiency), as was proven earlier. Al- Shawkani (d.1255/1839) articulated this brilliantly when he said: 'It is utter nonsense to say that Allah Almighty bestowed the capacity for knowledge and ijtihad on the bygone generations of ulema but denied it to the later generations.' ‘What the proponents of taqlid are saying to us is that we must know the Qur'an and the Sunnah through the words of other men while we still have the guidance in our hands. Praise be to Allah, this is the greatest lie (buhtanun 'azim) and there is no reason in the world to vindicate it.’ [Shawkani, Irshad, p. 254] The doors of Ijtihad are open but not for the ignorant, they are open until the day of judgement for the people of knowledge who have the capability to perform it.