Contrary to conventional assumptions, a deep and holistic analysis of the Qur'an proves decisively that religious pluralism and diversity is not merely tolerated, but is considered an integral manifestation of the very essence of Islam itself.

On the one hand, the Qur'anic-Prophetic model clearly saw itself as representing the perfection and pinnacle of Divine revelation to humankind, with many Qur'anic verses seeking to correct and rebuke past religious Jewish and Christian religious traditions for accumulating human distortions and errors, in terms of religious laws as well as conceptions of God, Prophethood, and other issues. In this sense, the Qur'anic-Prophetic model put itself forward as both a confirmation of the essential truths of past religious traditions, as well as a decisive corrective to alterations introduced by human communities through organised religious institutions. 

Despite this very firm corrective element in the Qur'an toward past religious traditions, there is nevertheless a continual dimension of affirming the inevitability of religious pluralism, and further in recognising that while the Qur'anic-Prophetic model supersedes previous traditions, it also recognises that they represented manifestations of Islam - the Way of Surrender - in their own historical contexts. 

Numerous verses indicate that religious diversity is a given, and that the attitude of Muslims toward non-Muslims of all persuasions should be fundamentally libertarian in nature: “Say : O you that reject Faith!  I worship not that which you worship, nor will you worship that which I worship.  And I will not worship that which you have been wont to worship, nor will you worship that which I worship.  To you be your Way, and to me mine.” (109:1-6)

During the Prophet’s lifetime, he was aware of people who routinely apostatised from and returned to Islam, yet this implied no worldly penalties – only spiritual deprivation: “Those who believe, then reject faith, then believe (again) and (again) reject faith, and go on increasing in rejection, Allah will not forgive them nor guide them nor guide them on the way.” (4:137) It is worth noting that Prof. Ahmad Shafaat of Concordia University in Montreal has convincingly demonstrated that the widespread presumption of a death penalty for apostasy is based on weak historical narrations, as well as cases where people were punished for violation of treaties and/or violent rebellion, rather than apostasy. (See Ahmad Shafaat, “The Punishment for Apostasy in Islam” and this perennial resource)

Similarly, numerous verses indicate that ‘Islam’ does not denote a single, historically-delimited form of religious exclusivism. On the contrary, Islam encompasses an unfolding, trans-historical reality with diverse manifestations in different communities, consisting fundamentally of recognition of the Divine Unity and submission to God through devotion to higher ethical principles.

The Qur'an calls on Muslims to see themselves as united with followers of other religious traditions, not counterposed against them. This is clear from the Qur’an’s repeated promises of salvation not to any particular religious group, but to all and anyone who sincerely endeavours to surrender to God:

“The [Muslim] believers, the Jews, the Christians, and the Sabians – all those who believe in God and the Last Day and do good – will have their rewards with their Lord. No fear for them, nor will they grieve.” (2:62)

And similarly:

“Surely, those who believe, those who are Jewish, the converts, and the Christians; any of them who believe in God and believe in the Last Day, and lead a righteous life, have nothing to fear, nor will they grieve.” (5:69)

In a number of verses, the Qur’an specifically condemns those who, on the basis of their revealed scriptures, indulge in disagreement and rivalry, disassociating this from ‘Islam’:

“True religion, in God’s eyes, is islam, those who were given the Scripture disagreed out of rivalry, only after they had been given knowledge – if anyone denies God’s revelation, God is swift to take account.’ (3:19)

The Qur'an also emphasises that salvation is not solely dependent on belief in any particular scripture, whether Islamic scripture, or the scriptures of 'People of the Book' (Jews and Christians). Rather, the criteria is sincere devotion to God:

“If they argue with you [Prophet], say, ‘I have devoted myself to God alone and so have my followers.’ Ask those who were given the Scripture, as well as those without one, ‘Do you too devote yourselves to Him alone?’ If they do, they will be guided, but if they turn away, your only duty is to convey the message. God is aware of His servants.” (3:20)

Corroborating this universal opportunity for salvation through ‘Islam’ conveyed fundamentally as form of surrender to God through ethical conduct, the Qur’an clearly guarantees that anyone is eligible:

“But we shall admit those who believe and do good deeds into Gardens graced with flowing streams, there to remain forever – a true promise from God. Who speaks more truly than God? It will not be according to your hopes or those of the People of the Book: anyone who does wrong will be requited for it and will find no one to protect and help him against God; anyone, male or female who does good deeds and is a believer will enter paradise and will not be wronged by as much as the dip in a date stone. Who could be better in religion than those who direct themselves wholly to God, do good, and follow the religion of Abraham, who was true in faith? God took Abraham as a friend.” (4:122-125)

In several other verses, the Qur’an reinforces the universalist message of unity in diversity by underscoring the existence of religious pluralism as part of the Divine Plan, and that this should not be a cause of rivalry or discord. There is a clear recognition that pluralism in religious practice is part of the Divine Plan:

“Each community has its own direction to which it returns: race to do good deeds and wherever you are, God will bring you together. God has power to do everything.” (2:148)

“For every community have We appointed sacred rites and ceremonies for them to follow: let them not dispute with you on the matter, but do invite (them) to your Lord: for you are assuredly on the Right Way.” (22:67)

In his extensive Qur’anic exegisis, Tafsir Al-Mizan, Grand Ayatollah Muhammad Husayn Tabataba'i concludes from these verses that “the criterion and reason for moral nobility and ultimate felicity is a genuine faith in God and the Last Day and good deeds... None of these names (religious affiliations and labels) benefit their bearers and no quality leads to salvation except adherence to humble veneration of God (ubudiyyah).” (Cited in Seyed Amir Akrami, “Particularity, Universality and Finality in Revelation”, Birmingham: Al-Mahdi Institute, May 2008, p. 7. See this paper for a compelling elucidation of the argument made here) 

When read against the context of the preceding verses, the following assertion in the Qur'an of the perfection and finality of Islam as revealed through the Prophet Muhammad takes on a universalistic meaning, in which the perfect religion of 'surrender' involves acceptance and recognition of the validity and plurality of the various manifestations of 'islam' in history. 

"This day I have perfected for you your religion and completed My favour upon you and have approved for you Islam as religion." (5:3)

Thus, ‘Islam’ is not identified with just one particular historical form, but with the universal thread of Divine revelations passing through the diversity of humankind’s different religious traditions. The Qur'an emphasise that despite their differences, these religions were in fact past distillations of the message of 'Islam', calling for surrender to the Divine Unity. This verse describes the Qur'anic-Prophetic model as the final culmination of this universal message in its ultimate form, while simultaneously exhorting that part of following this model must involve accepting and respecting the historical reality of multiple Divine revelations of 'Islam' through different religious traditions.

In this sense, the Prophet's 'Islam' functions as a reminder of that universal message in human history, an affirmation of the unifying values within those diverse traditions, and a correction to the mistakes of past faith communities based on irrationality, superstition, and egoism - and call for a return to the 'primordial religion' of humankind, which the Qur'an says is 'Islam' as finally encapsulated in the Qur'anic-Prophetic model . 

"Say: We believe in God, and in that which has been bestowed from on high upon us, and that which has been bestowed upon Abraham and Ishmael and Isaac and Jacob and their descendants, and that which has been vouchsafed to Moses and Jesus, and that which has been vouchsafed to all the [other] prophets by their Sustainer: we make no distinction between any of them. And it is unto Him that we surrender ourselves." (2:136)

Simultaneously, while positing that Islam as finalised through the Qur'anic-Prophetic model is a culmination of the historical process of Divine revelation, the Qur'an also emphasises that this should not be a basis for discord with other religious traditions, nor should Muslims assume that salvation is assured exclusively to Muslims simply because they are Muslims, and that part of the Qur'anic-Prophetic model is to accommodate and protect religious pluralism. In other words, the Qur’anic conception of the perfected Islam is of a universal disposition of surrender toward the Divine Reality available to all, an acceptance of the diversity of the manifestations of the Way of Surrendering in history and different societies, and an encouragement to these different communities to work together to increase their capacity for ethical conduct, in both inward orientation and outward form.

This is what the Prophet came to reveal through the Divine revelation of the Qur'an. And this is what an authentic Muslim is asked to affirm and practice.