Religion is a set of beliefs associated with practical and moral principles delivered to humankind by God's messengers, for the guidance of man and his eternal prosperity and salvation.
According to religious teachings, the necessity of religion is rooted in the fitrah (nature) of man. In the holy Quran, the fitrah is characterized as a divine one, that all of His orders and laws are in complete harmony with [meaning that there isn't a divine law that the fitrah rejects and cannot accept].
In the holy Quran, all monotheistic religions have common principles and teachings which are based on the submission to the will of the One God. The subsequent religion has always complemented the previous one, and the highest of them all is the one that complements all previous ones. This final and most complete religion is the one Prophet Muhammad (PBUH) was sent to preach and promote during the last 23 years of his life.
This question actually goes back to the general question about why we need religion, and about what the status of Islam is amongst other religions.
We can address this question both from an outer and an inner perspective, but first we need to explain what the term religion itself denotes.
What is religion?
Religion is a set of beliefs associated with practical and moral principles delivered to humankind by God's messengers, in order to show human beings the right path. For God, this religion is the absolute submission of the people to His guidance and is in harmony with their fitrah.
Possessing these beliefs and abiding by the principles presented by them brings man salvation and felicity in this world and the next. In other words, the “religious” individual is one who submits to this divine plan, therefore one who doesn’t, in no way can be called a religious person.
If people choose to be faithful and go by God's rulings, they will have a happy life in this transient world and also in the eternal one to come, because the happy and prosperous individual is one who has the right goal in his/her life, stays away from error and deviance, possesses good and admirable characteristics, carries out good deeds and always preserves his/her calmness in the vicissitudes and hardships of life.
God's religion guides us to this path. Otherwise, salvation and felicity can never be reached, because when one is destined to abide by religious principles, he is like a person who is always being accompanied by an alert inner “guard” who is always on the watch and careful for him not to commit anything that will contribute to his downfall and decline, and this results in his prosperity and possession of virtues. Naturally, one who doesn’t possess this inner “guard”, has no chances for reaching such ranks. Now that the meaning and the role of religion have been made clear, we will address its necessity.
a. The necessity of religion from an outsider perspective:
The need for worshipping and following a divine plan for life can somewhat be considered man’s double from the beginning of creation. Allamah Tabataba'i has two approaches in arguing for the necessity of religion:
1. Man is a utilizing creature.
2. Utilizing others is rooted in his nature.
3. This characteristic of man brings conflict into all aspects of his life.
4. The order of creation calls for these conflicts to be solved so that man can achieve his true perfection.
5. Resolving these conflicts is impossible, unless there is a code of law that reforms social life and guarantees salvation and felicity.
6. Man’s nature cannot accomplish this task, because as was said, it was the very cause for all of the conflicts.
7. The conflicts will not be solved by a man-made code of law.
Based on these premises, it is necessary for God Almighty to show man the right path through a supernatural way, that being revelation.
1. Man is one of the constituting parts of the universe.
2. The creation has provided him with a system in which prepares the grounds for his perfection.
3. Man has been created in a way that leaves with no choice but to live a social life and interact with others.
4. He is eternal and isn't to perish through death [death is only a transferring stage].
5. Man needs to live a life that guarantees him prosperity and happiness both in this life and the eternal one to come.
6. The set of guidelines that targets this goal is called religion.
Since man’s knowledge and horizons are limited, he cannot devise a perfect and complete program for himself. He has to follow the guidelines of an unlimited source, which is God Almighty. This program that aims for the salvation of mankind is called religion.
B. The necessity of religion from an inner perspective:
The necessity of religion, according to religious teachings, is rooted in the Fitrah and nature of man. The holy Quran regards this nature as a divine one in which all divine commandments and rulings are in harmony with [meaning that there is no divine law and commandment that man’s nature rejects and just cannot accept]. Thus, following religion and being religious and Muslim is a natural response to the call of one's own fitrah.
Advantages and outcomes of religion
Religion is strongly influential in reforming the society and the individual. Indeed, it is the only way to salvation and felicity.
A society that does not abide by religious principles loses prudence and enlightenment; its people wasting their precious lives in ignorance and benightedness, dismissing the intellect, living animalistic lives and degrading themselves with corruption and wickedness. Such a society loses all human characteristics. Far from achieving its ultimate perfection and eternal salvation, it will face the horrible consequences and detrimental upshot of its deviance. Eventually and wistfully it will reach the conclusion that religion and faith in God were the only true way to salvation.
God almighty states, "He will indeed be successful who purifies it. And he will indeed fail who corrupts it."
It should be noted that what brings individual and social felicity is the implementation religious laws, not merely purporting to being religious. A so-called Muslim who has corrupt characteristics and wicked actions and nevertheless anticipates salvation is like a sick person who expects recovery by merely keeping the doctor's prescription in his hand.
Allah (swt) says: "Surely those who believe, and those who are Jews, and the Christians, and the Sabians, whoever believes in God and the Last day and does good, they shall have their reward from their Lord, and there is no fear for them, nor shall they grieve".
Some might think this verse is indicating that those who believe in God and the hereafter and perform good deeds will achieve salvation, even though they may have rejected all messengers or some of them. But this conception is wrong, because God almighty states in another verse, " Those who deny God and His messengers, and (those who) wish to separate between God and His messengers, saying: 'We believe in some but reject others'; and (those who) wish to take a course midway, they are in truth unbelievers."
Accordingly, only those who accept all of Allah’s (swt) messengers and perform good deeds will benefit from their faith.
Islam etymologically derives from "سلم" which means to surrender or submit. This is the name that Allah (swt) has chosen for His religion in the Quran. The true religion in the sight of God is “islam” (in its literal sense, which is submitting to the truth [so during the time of Prophet Isa (pbuh), one who embraces his religion is a true muslim, meaning that he has truly submitted to Allah (swt) by following the messenger of his time]).
Islam is one of the monotheistic faiths, which was promoted by the Prophet Muhammad (PBUH) around 610 C.E. in
The holy Quran which is the most authentic Islamic resource in our hands today, never differentiates between God's messengers; indeed, according to the Quran, all of Allah's (swt) messengers were promoting the one religion of Islam (submission) but with different manifestations. The fundamental teaching of this religion is submission to God's will. It is on this basis that sometimes in the Quran, what is meant by the term “Islam” is the “total submission to God” that can be found in all divine religions rather than meaning the specific religion of Islam that is the seal of religions. The most perfect instance of this “submission” is the religion that complements all previous ones, which the Prophet Muhammad had the mission to promote during the last 23 years of his life.
Islam is, therefore, the continuation and completion of all previous divine religions. No distortion has occurred in this religion. Unlike other religions, Islam contains regulations both for worldly issues and for leading a spiritual life. On one hand, although ascetic life is praised, monasticism has no place in Islam and on the other hand, while encouraging the right enjoyment of God-given worldly blessings, Islam censures excessive attachment and love for the material world. With Islam, all previous religions are abrogated. Once there is a complete religion, there is no longer any need for an incomplete one.
Moreover, Islam is a universal and everlasting religion, which, when correctly understood, is sufficient for regulating the life of all people in all times. Whether young or old, literate or illiterate, man or woman, white or black and western or eastern, everyone can benefit from this pure faith and satisfy their needs in the best and most perfect way, because the foundation of Islamic teachings and laws is the man’s fitrah, which is the same in all people and all times, resulting in Islam being enough for all people in all times as well.
For further reading, see:
1- Seyyid Muhammad Husein Tabatabai, Kholaseye Ta’alime Islam.
2- Mehdi Hadavi Tehrani, Velayat va Diyanat.
3- The fundamentals and pillars of Islam, Question 1413 (website: ).
4- The meaning of “Islam”, Question 2452 (website: ).
5- Islam and the demands of eras, Question 749 (website: ).
 Seyyid Muhammad Husein Tabatabai, Kholaseye Ta’alime Islam, pg.4; Abdullah Javadi Amoli, Fitrat dar Quran, vol.12, pg.145.
 Tafsir Roshan, vol.7, pg.170.
 Seyyid Muhammad Husein Tabatabi, Barresihaye Eslami, pp. 35-37; Farazhayi az Eslam, pp. 23-25.
 Quran 30:30
 Quran 91: 9-10
 The Sabians were the Jews who mixed their Judaism with the Magian religion.
 Quran, 2:62
 Quran, 4: 150-151
 Quran 2:136
 Quran 3:19, 83, 85; 5:44
 Quran 5:3
 Quran 5:3
 Quran 7:32