When a person comes to this world, he does not have knowledge about anything. That is why there is no other way except that he learns from the experience of others. This is the reason why a person whose life is full of up's and downs requires knowledge at every step.
Basically, life is based on two main pillars and they are to know and then to implement them and for implementation knowledge is necessary. That is why the life's first step starts with knowledge.
This is the stage when a person's natural instincts help him and life opens the way of perfection and happiness for him. This instinct is called derivation and following. As we all know that a child, who because of the movements from his inner self learns from his parents how to talk and the manners of sitting and standing and in this way passes one stage of life from the other.
And as the child grows he learns and gains from knowledge and thinking of others and tries to pay attention to following them. Slowly he becomes aware about the existence of this world and then starts performing his duties.
But here it is important to mention a basic thing that blindly following the views and manners of anyone completely is not correct. Rather following (Taqlid) is of different types:
It is as clear as the sun that this type of Taqlid not only makes a person's life miserable. Unfortunately in our society many such people are present who follow other people's ethics and their way of life blindly.
They copy other people in dressing eating and drinking, naming their children and in other spheres of life. They also follow the prohibited things, false beliefs and bad ethics under the attractive titles, without understanding them although the evil of this type of following is clearly evident. Regarding this type of Taqlid it is said:
They say: We found our fathers on a course, and surely we are guided by their footsteps.1
The Qur’an has severely refuted this logic and denounced those people.
It is clear that this type of Taqlid is worse than the first and it is more dangerous, because it is expected from a learned person that he should act according to his knowledge in order to carry out his responsibilities. The worst kind of Taqlid is that a learned person doesn't use his knowledge and follow the others blindly.
One Aalim who is well versed in one field and has authority over it should not do the Taqlid of another who also has the same caliber, but he should act according to his knowledge, that is why the Jurisprudents say that when a person reaches the stage of ijtehad, he should then practice according to it. That is the reason why it is generally mentioned on the certificate of Ijtehad: Taqlid is Haraam for him.
And it is necessary that he should practice according to his knowledge although there is no problem if he exchanges his views on religious problems with other scholars. The aim is that an Aalim should make a rule and then protect it and should not accept the principles of others without study.
This type of Taqlid is accepted by intellect and nature of man and this type of Taqlid is demanded by them. This is as logical to construct a building we require a mason and for stitching clothes we require a tailor and when we are ill, we go to a doctor. In short intellect and nature direct us towards the person who is expert in his field.
This is the same logic, which directs the people towards jurisprudents for religious instructions and spiritual laws, who are expert in understanding the commands of Allah.
Those jurisprudents that with their special talent and knowledge have worked hard for years, and reached the high level of Ijtehad. If means there have the ability to derive the original matter of the spiritual commands and convey it to the ordinary people.
Those Mujtahids who are the religious leaders and guides of people, who got this great positions from the Holy Imams (a.s.), so that they can guide people towards goodness in all religious spheres.
Here we should not ignore that there are different faculties of Human Science and it is possible that a person might have a special knowledge and expertise in one section but may be totally unaware of another and as a result it is necessary for him that in the field in which he is totally ignorant he should contact those who are experts in that field, and follow them.
For example a doctor or an engineer who are expert in their respective fields enter a town and want to go to a particular area and a particular street, about which they are unaware of, but they were only been given the address. In this matter to reach the destination they will be forced to seek the guidance of people who reside in that area.
Or for example an environmentalist, who becomes ill, is forced to go to a physician; although this person knows about environment he doesn't know about diseases and their cure. There is no way except that he should go to a doctor and take the medicine or injection. He should not grumble and follow the instructions carefully and he doesn't ask why the doctor has prescribed such and such medicine.
Keeping these two examples in mind, it becomes clear that even if the person is an expert in his own field he should he follow the rulings of a Mujtahid. The reason is that a Faqih (jurisprudent) is expert in his field. He is expert in many sciences, which are his basis in jurisprudence. (Sarf, Nahv, Arabic literature, logic, exegesis, the knowledge of the traditionalists, sources, traditions, the roots of jurisprudence, interlocution etc).
By seeing a small book called Tauzihul Masael you may not know that it is the result of lifelong toil of a Mujtahids. He has written it only after putting blood of his heart in it and only then he has presented it to the common people. Ijtehad is not easy. Ijtehad means to acquire the knowledge of all the Islamic laws, which affect a person or the whole society, and in all spheres of life.
Shaykh Murtaza Ansari, who was a great Mujtahid himself and the proud son of Islamic Jurisprudence who himself took lot of trouble and hard work to become a Mujtahid says in his book Rasael: Allah has given us the opportunity of Ijtehad, which is tougher than continuous Jihad and much more painful.
It is necessary to say that Taqlid of a Mujtahid is not in articles of Faith but it is related to the practical law. In other words it is necessary to follow a Mujtahid in the rules, regulations and branches of religion and not in the roots of religion. It is so because Allah, the most High and the recognition of the Holy Prophets are the basis of religion, and to know them through logic and arguments is necessary.
So that after accepting the roots of religion with logic and arguments, in the branches of religion (whose religious source like the glorious Qur’an and traditions and to understand the other proofs, it is necessary to know different branches of knowledge and to be expert in it) we must refer to Mujtahids who are expert and authority in this field.
Islam's established laws and orders like Prayers, Hajj, Zakat (tax), are compulsory. Enjoining towards good, refraining from evil, lying, breach of trust, backbiting, wine, etc. which are prohibited and there is no need to follow a Mujtahid for them as these are known by everyone, therefore Taqlid is limited up to those laws and orders which are not absolutely established.