By Shaykh Muhammed ibn Saalih al-Uthaymeen
Definition of ljtihaad
Linguistically ijtihaad means: to expend efforts in order to reach some difficult matter. Technically it means: expending efforts to arrive at a Shariah ruling. And the mujtahid is the one who expends efforts for this purpose.
Conditions for ljtihaad
Being a mujtahid has conditions, such as,
 That he knows the Shariah proofs which he needs in his ijtihaad such as the aayaat (verses) and Hadith pertaining to rulings.
[21 That he knows what relates to the authenticity or weakness of a Hadith, such as having knowledge of the isnaad (chain of narration) and its narrators, and anything other than this.
[31 That he knows an-naasikh (the abrogating) and al-mansookh (the abrogated), and the places where there is ijmaa’ -(consensus) such that he does not give a ruling according to something that has been abrogated, nor gives a ruling opposing the [authentically related] ijmaa’.
 That he knows from the proofs, that which causes the rulings to vary, such as takhsees (particularisation), or taqyeed (restriction), or its like. So he does not give a judgement which is contrary to this.
 That he knows the Arabic language and usoolul-fiqh (fundamentals and principles of jurisprudence), and what relates to the meaning and indications of particular wordings - such as al—’aam (the general), al-khaass (particular), al-mutlaq (the absolute and unrestricted), al-muqayyid (the restricted), al-mujmal (the unclarified), al-mubayyin (the clarified), and its like - in order that he gives a ruling in accordance with what this demands.
 That he has the ability to extract rulings from the evidences. And ijtihaad may be split-up, such that it may be undertaken in one particular branch of knowledge, or in one particular mas’alah (issue).
What is Essential for the Mujtahid
It is essential that the mujtahid strives in expending his efforts to arrive at knowledge of the truth, and to give rulings in accordance with what is apparent to him. If he is correct, then he has two rewards: one for his ijtihaad, and the other for arriving at the truth -since arriving at the truth means that it is manifested and acted upon. If, however, he is mistaken, then he has a single reward, and his error is forgiven for him - as the Prophet (Pbuh) said: “When a judge judges and strives and is correct then he has two rewards. If the judge strives and errs, then he has a single reward. If the ruling is not clear to him, then he must withhold - and in such a case, taqleed is permissible for him, due to necessity.”
Taqleed: its Definition
Linguistically, taqleed means: Placing something around the neck, which encircles the neck. Technically it means: Following he whose saying is not a hujjah (proof).
Excluded from our saying: “Following him whose saying is not a proof.” Is: following the Prophet (Pbuh), following the people of ijmaa’ (consensus) and also following the saying of a Sahaabee (Companion) - for those who consider the saying of a single Sahaabee to be a proof So following any of these is not called taqleed, since there is proof for doing so. However, this type of following is sometimes referred to as taqleed in a very metaphorical and loose sense.
The Place of Taqleed:
Taqleed is done in two cases:
Firstly: when the muqallid (person performing taqleed) is an ‘aamee (a common person) who does not have the ability to acquire knowledge of the Shariah ruling by himself. So taqleed is obligatory upon him, due to the saying of Allah - the Most High: “Ask the People of Knowledge if you do not know.” So he does taqleed of one whom he considers to be a person of knowledge and piety. If there are two such people who are equal in his view, then he chooses any one of them.
Secondly: The mujtahid when he encounters a new situation, for which an immediate solution is required, but it is not possible for him to research into the matter. So in this case he is permitted to perform taqleed. Some stipulate as a condition for the permissibility of taqleed, that the matter is not from the fundamentals of the Deen - those matters which must be held as -aqeedah (belief) since matters of ‘aqeedah require certainty, whereas taqleed only amounts to dhann (knowledge which is not certain).
However, the correct saying in this matter is that this is not a condition, due to the generality of His - the Most High’s - saying: “Ask the people of knowledge if you do not know.” And this Aayah (verse) is in the context of affirming Messengership which is from the fundamentals of the Deen. And also because an `aamee cannot acquire knowledge of the Shariah rulings with its proofs by himself So if he is unable to arrive at the truth by himself, then nothing remains for him except taqleed, due to the saying of Allah - the Most High: “Fear Allah as much as you can.
Types of Taqleed
Taqleed is of two types: general and specific.
 The general type: that a person sticks to a particular madhhab (school of thought), accepting its concessions and non-concessions, in all the matters of his Deen.
The Scholars have differed about such a state. So some amongst the late-comers have reported that this is obligatory upon him, due to his inability to perform ijtihaad. Others report it as being forbidden for him, due to its being a case of necessitating unrestricted following of someone other than the Prophet (Pbuh).
Shaykhul-Islaam Ibn Taymiyyah (d.728H) said: “The saying that it is obligatory, causes obedience to someone other than the Prophet (Pbuh) in every matter of command and prohibition, and this is in opposition to the ijmaa’ (consensus). And allowance of it contains what it contains.”
He also said: “He who sticks to a particular madhhab (school of thought), and then acts in opposition to it - without making taqleed of another Scholar who has given him a ruling, nor uses an evidence as a proof which necessitates acting in opposition to his madhhab, nor has an acceptable Shariah excuse which allows him to do what he has done - then such a person is a follower of his desires, doing that which is haraam (forbidden) - without a Shariah excuse - and this is evil and sinful.
However, if there becomes clear to him, something which necessitates preference of one saying to another - either due to detailed proofs if he knows and understands them, or because he holds one of the two people to be more knowledgeable about this matter and having more piety with regards to what he says - and so he leaves the saying of that one for the saying of the other one, then this is permissible, rather, it is obligatory. And there is a text from Imaam Ahmad about this.
[ 2 ] The particular type of taqleed is that he accepts a saying about a particular matter. This is permissible if such a person is unable to arrive at knowledge of the truth by ijtihaad - whether he is unable in reality, or he is able, but with great difficulty.
Fatwaa of a MuqaIlid
Allaah - the Most High - said: “Ask the people of Knowledge if you do not know.” And Ahludh- are Ahlul-Ilm (the people of Knowledge), whereas the muqallid is not a person of knowledge who is followed - rather he himself is a follower of someone else.
Ibn ‘Abdul-Barr (d.463H) and others have said: “The people are united in ijmaa’ that the muqallid is not counted as being from Ahlul-’Ilm, and that al-ilm (knowledge) is the realisation of the guidance along with its proof.”
Ibn al-Qayyim (d.756H) said: “And it is as Abu ‘Urnar (Ibn ‘Abdul-Barr) said: Indeed, the people do not differ about the fact that al-’ilm (knowledge) is the realisation attained from a proof, but without proof, it is only taqleed.
Ibn al-Qayyim then quotes:“There are three sayings about the permissibility of giving a fatwaa (legal verdict) based upon taqleed:
Firstly: It is not permissible to give a fat-waa based upon taqleed, because it is not knowledge, since issuing a fatwaa without knowledge is forbidden. This is the saying of most of the Hanbalee Scholars and the majority of Shaafi’yyah.
Secondly: That it is permissible with regards to oneself, but it is not permissible to give a fat-waa to others based upon taqleed.
Thirdly: That it is permissible when there is a need for it, and there is no mujtahid Scholar available. And this is the most correct of the sayings, and it is what is acted upon.” (Courtesy Al-Ibaanah Magazine, www.call-to-islam.org.uk)