In order to establish peaceful religious coexistence in society, Islam has suggested four principles.
No Compulsion in Religion
No doubt there are different factors involved in forming people's opinions and faiths. The physical structure and the organic compounds, time, place, diet, education, and so many other factors have inevitable effects on people's faiths. Thus, the healthy way to change their opinion is to encounter them from their origins. Utilizing force and compulsion not only cannot change the hearts of people, but it may in many instances increase hatred and animosity.
To this end, the Holy Qur'an clearly denounces the use of the force in terms of religion. It is ultimately the right of people to choose any religion they are happy with, and the duty of the Prophets is not more than educating people and reminding them of the Right Path. They have never been authorized to force people to the Truth.
The following verses are the examples of many:
"Let there be no compulsion in religion; Truth stands clear from error." (2:256)
"If it had been the Lord's Will, all who are on earth would have believed. Will you then compel mankind against their will to believe?!" (10:99)
"Say, the Truth is from your Lord, let him who will believe, and let him who will reject." (18:29)
"And you are not the one to overawe them. Therefore, remind with this Qur'an those who reverence My warnings." (50:45)
"You shall remind, for you are the reminder. You are not one to manage (men's) affairs." (88:21-22)
"Enlightenment has come to you from your Lord. As for those who can see, they do so for their own good, and those who turn blind, do so to their own detriment. I am not your guardian." (6:104)
"If they reject you, then say: 'My work to me and yours to you. You are free from the responsibility of what I do and I for what you do.'" (10:41)
"The sole duty of the messenger is to deliver the message, and Allah knows everything you declare and everything you conceal." (5:99)
"If they argue with you, then say I have simply submitted myself to God; I and those who follow me. And you shall proclaim to those who received the scripture as well as those who did not, 'would you submit'? If they submit then they have been guided, but if they turn away, your sole mission is to deliver this message. God is Seer of all people." (3:20)
"You shall obey God and you shall obey the messenger, and beware if you turn away, then know that the sole duty of our messenger is to deliver the message efficiently." (5:92)
The above verses utterly denounce the practice of inquisition and pressuring the followers of other religions in order to change their beliefs. Nevertheless, preaching and enlightening people is permitted and is the duty of the messengers in a logical manner.
Logical Debate and Discussion
While respecting other religions and beliefs, Islam may disagree with some of their teachings, finding them illogical, and hence invites their adherents to open discussion and debate in a peaceful and logical manner far from any type of fanaticism and prejudice.
The following verses are the examples of this approach:
"And dispute you not with the People of the Book except with means better (than mere disputation) unless it be with those of them who inflict wrong. But say, 'We believe in the Revelation which has come down to us and in that which came down to you, our God and your God is One, and it is to Him we submit.'" (29:46)
"Invite all to the way of your Lord with wisdom and beautiful preaching, and argue with them in ways that are best and most gracious." (16:125)
"So announce the good news to My servants, those who listen to the word and follow the best of it. Those are the ones whom Allah has guided and those are the ones endued with understanding." (39:17-18)
"Say: produce your proof if you are truthful." (2:111, 21:24, 16:64, 9:6)
Divine Religions: Grades of One School
Judaism, Christianity, and Islam have a great deal in common. They are all based on monotheism and are committed to increasing justice in the world and the accountability before God. Their historic roots go back to Prophet Abraham (peace be upon him), and as such, they are often described as 'Abrahamic Faiths'. They are also the basis of great world civilizations.
Therefore, despite the followers of other religions who consider themselves the chosen nation and the only saved ones, Islam considers all of the divine religions as different grades of the one school. From the Islamic point of view, each new divine religion has been the upgraded version of the previous one, prescribed to complete its teachings.
All of the Prophets are the teachers of one school, teaching different grades according to the requirements of the people of their age. Hence, if hypothetically all of them descend to earth, they would live together peacefully and each would acknowledge his successor and the one who has come after him.
An old debate has gone around among the followers of different religions as to who will go to hell and who to heaven. The followers of each religion with no hesitation claim eternal life in heaven for themselves, and see hell as the place for all who oppose them. Islam, despite this fanaticism, suggests a very liberal idea. The following verses vividly reveal this idea.
"They say: 'Become Jews or Christians if you would be guided.' Say, 'Nay! (I would rather) the religion of Abraham, the True, and he joined no gods with Allah.' Say, 'We believe in God, and in what was sent down to us, and in what was sent down to Abraham, Ismail, Isaac, Jacob, and the Patriarchs; and in what was given to Moses and Jesus, and all the prophets from their Lord. We make no distinction among any of them. To Him alone we are submitters.'" (2:135-136)
"And they say: 'None shall enter Paradise unless he be a Jew or a Christian.' Those are their (vain) desires. Say produce your proof if you are truthful. Yes, whoever submits his whole self to Allah and is a doer of good, he will get his reward with his Lord, on such shall be no fear, nor shall they grieve." (2:111-112)
"Those who believe (in Islam) and those who follow the Jewish (Scriptures) and the Christians and the Sabians, any who believe in Allah and the Last Day and work righteousness, shall have their reward with their Lord; on them shall be no fear, nor shall they grieve." (2:62)
The Principle of Righteousness and Justice
The last suggestion prescribed by Islam to achieve harmony among people of different cultures and religions is that Islam has always advocated for the principle of justice and righteousness within humankind. Muslims are encouraged to deal kindly and justly with all people, Muslims and non-Muslims alike, with the exception of those who are fighting Muslims. The Holy Qur'an revealing the above fact utters:
"Allah forbids you not, with regard to those who fight you not for your faith, nor drive you out of your homes, from dealing kindly and justly with them, for Allah loves those who are just." (60:8)