By the branches of the religion we mean those religious laws which govern our action (shan’ah), but concerning which not everyone is required to exercise juristic reasoning (ijtihad). However, it is the duty of everyone to take one of the three following ways in regard to them:

(a) he should exert himself in study until he becomes a Mujtahid,
(b) he should exercise juristic precaution (Ihtiyat) if he is able to,
(c) he should follow one who is a recognised Mujtahid, who must be a man of wisdom and justice, “who keeps himself away from sin, not following the dictates of his own desires, but obeying the commands of Allah.

It follows that one who is neither a Mujtahid, nor exercises Ihtiyat, nor follows a Mujtahid, does all the actions of his din in vain, and that neither his prayer nor his fasting will be accepted by Allah, even though he has carried out his duties in these matters for the whole of his life; unless he begins to follow a Mujtahid, in which case, those of his actions prior to his following the Mujtahid which were done for the sake of Allah will be accepted.

Doctrine of the Necessity for Juristic Reasoning

We believe that Ijtihad in matters of religion is a sufficient necessity (Wajib-e-Kifa’ei) for all Muslims in the absence of the Imam, that is to say that should one of them become proficient in Ijtihad and become a Mujtahid it is enough for them to follow the Mujtahid in all the branches of the religion.

All Muslims must strive to gain knowledge and to ascend to the position of Mujtahid, or, if that is not possible, they must give all their encouragement to one of their number to attain this position. If no-one living holds the position of Mujtahid, it is not permissible to follow a dead Mujtahid. Ijtihad is the examination of the sources of the Shari’ah to reach knowledge of the commandments (al-Ahkam al-Fariyyah) which the Prophet brought with him, and which do not change or alter with changes in time or situation, according to the hadith : “What Muhammad (s.a.w.a.) made Halal will be Halal till the Day of Judgement, and what he made Haram will be Haram till the Day of Judgement.” These sources for the Shari’ah are Qur’an the Sunnah (of the Prophet and the Imams), consensus (Ijma) and reasoning (’aql), as have been mentioned in the texts of usual al-Fiqh. Attaining the position of Mujtahid requires many years of study and acquiring knowledge, and this is not obtained except by one who tries his utmost.

Doctrine concerning the Position of Mujtahid

We believe that a fully qualified mujtahid is representative of the Imam, in the case of the latter’s absence. Thus he is an authority over Muslims and he performs the functions of the Imams regards judgement and administration among the people, Because of this, Imam Ja’far as-Sadiq said: To deny the authority of a mujtahid is to deny the authority of the Imam, and to deny the authority of the Imam is to make an objection to the authority of Allah, and this is tantamount to polytheism (shirk). Ref: Wasaaelush Shia, Vol.18.

Therefore the qualified mujtahid is not one who issues fatwas, but he also has general authority over Muslim who must consult him if they require judgement, this being obtainable only from him. it is correspondingly wrong for anyone to give judgement except him or one who is appointed by him, as no-one can pass sentence without his permission. Also, all that which belongs to the Imam should be given to the mujtahid. Such authority has been bestowed upon the qualified Mujtahid by the Imam so that he may represent him in his absence; hence he is known as the ordinary representative of the Imam (naib al-imam)

The definition and qualifications of a mujtahid

A mujtahid is an expert in Islamic Law who has the ability to deduce the principles and secondary laws from the original sources of Islam (Qur’an) the Tradition and Practise of the Prophet and the Imams (sunna), consensus (ijma), and reasoning (‘aql). A mujtahid who is to be followed must possess the following qualifications, he must be:

1. male
2. sane
3. of legitimate birth
4. past the legal age of puberty
5. living
6. an Ithna-‘ashari (Twelver) Shi’i
7. in possession of the attribute of probity (‘adala)

In addition the mujtahid who is followed must be the most learned mujtahid of his time, the one who is the most proficient at deducing the laws of the shari’a

How to recognise a Mujtahid and the most learned one There are three ways:

1. one should gain certainty through one’s own knowledge,
2. one should rely on the testimony of two or more knowledgeable persons of probity,
3. if it is commonly accepted by the knowledgeable that a person is a mujtahid or the most learned mujtahid of his age, one can gain certainty from the widespread nature of his renown.

The following of the most learned mujtahid is an obligation in the law, but it can be understood by comparing the situation of one seeks to know his duty before the religious law with a sick person, or someone involved in a dispute in a secular court of law. A person who is ill will seek to obtain the best medical advice he can, and the litigant or defendant will seek the best legal advice he can. In following the precepts of the shari’a it is similarly reasonable to seek the best counsel, but because of the gravity of one’s conduct before God, Islam has prescribed the following of the most learned mujtahid and has not merely left it to us as an option.

Probity has also been made a condition for the mujtahid who is followed because it is only when a mujtahid is seen to be acting fully in accordance with his learning and knowledge that it can be understood that he is doing so for no other reason than a desire to submit completely to god’s will. According to Shi’i law, the mujtahid who is followed must be living; the only exception is when a person followed a mujtahid when that mujtahid was alive & has committed his rulings to memory, & it is then permissible for him or her to continue following the rulings of that mujtahid after he has died, as long as he has the permission of a living mujtahid to do so. It is in this way that Shi’i law ensure that the believer is always able to obtain a ruling for every new occurrence and in the face of changing material and social conditions.