History, Diversity, and Interfaith Relations

The process varied by place and century, and it helps to separate two things that are often conflated: the spread of Muslim rule and the spread of the Islamic faith.

Muslim rule expanded rapidly in Islam’s first century through conquest, as the newly unified Arab tribes came into conflict with the Byzantine and Persian empires, which was a military expansion of the kind that built most empires of that era. The spread of the faith was a different and much slower story. Muslim rulers did not force, and often did not even encourage conversion; conquered populations remained Christian, Jewish, Zoroastrian, or Hindu for generations, and historians estimate that majorities in the central Islamic lands did not become Muslim until centuries after the conquests. The historian Ira Lapidus, surveying the evidence in A History of Islamic Societies, notes that older European assumptions of “conversion by the sword” have not held up: forced conversion occurred but was rare, rulers were more interested in governing (and taxing) than converting, and most conversion was voluntary: through intermarriage, trade, social integration, and the missionary work of Sufi spiritual teachers.

Vast regions of the Muslim world, moreover, were never conquered at all. Indonesia, today the largest Muslim-majority country, along with Malaysia and much of Southeast Asia embraced Islam through merchants and Sufis; the same is true of much of West Africa and the Swahili coast, where trade and scholarship carried the faith. Islam’s continuing growth today, including in the Americas and Europe, proceeds the same way: through families, migration, and individual conviction.

The majority of both Sunnis and Shi‘a share the core beliefs of Islam, the oneness of God and the prophethood of Muhammad, and adhere to the Five Pillars.

Historically, the split originated in a dispute over who should lead the Muslim community after the death of the Prophet Muhammad. While both the majority of Sunnis and Shi‘a assign special status to and revere the descendants and family of the Prophet Muhammad, Shi‘a believe that succession to the spiritual and political rule of the Muslim community lies only with the family and certain descendants of the Prophet Muhammad. Specifically, Shi‘a believe that God chose Muhammad’s cousin ‘Ali, who was married to his daughter Fatima, to be the Prophet Muhammad’s successor, and that Muhammad indicated this before his death. In support of their position Shi‘a cite a sermon by the Prophet Muhammad shortly before his death at a place called Ghadir Khumm, in which he stated “to whomever I am mawla, ‘Ali is also their mawla.” The point of contention is the meaning of the word mawla; the Sunni interpretation of mawla here is “friend,” whereas the Shi‘i interpretation is “master,” which includes political leadership. Shi‘a also view ‘Ali as the first in a line of Imams, or preeminent religious leaders, whom they regard as the spiritual and political successors to Muhammad.

In contrast, Sunnis believe that the Muslim community was free to choose the most qualified person as ruler and that Muhammad did not appoint any particular person as his political successor, although he lauded his kinsmen, descendants, and companions as the spiritual heirs of his teachings.

This difference in interpretation affected not only political leadership but also the development of Islamic theology, as each group had different methods of exegetical approach to the Quran and different criteria for authenticating Hadith. The main differences between them today are their sources of knowledge and religious leadership. In addition to the Quran and Hadith, Shi‘a rely on the rulings of their Imams, while Sunnis rely on the rulings and consensus of their scholars, resulting in variations in beliefs and practices. It should be noted that both communities represent authentic attempts to interpret the Quran and put the teachings and example of the Prophet Muhammad into practice.

The Sunni-Shi‘i schism began as a dispute over political succession and eventually evolved into a theological one as well, not unlike the schism of 1054 between the Eastern and Western Churches.

Shi‘a maintain that the right of succession for the leadership of the nascent Muslim community after the death of the Prophet Muhammad went to ‘Ali, the cousin and son-in-law of Muhammad, while Sunnis believed that the choice of Abu Bakr, father-in-law and close confidant of Muhammad, and of the subsequent three caliphs or rulers was valid. When ‘Ali was finally chosen as the fourth caliph or ruler, his rule was short-lived, and after his death his rival Mu‘awiya quickly asserted his power and established Umayyad rule.

Many practices of the Umayyad dynasty, which had adopted a pattern of rule and succession that was starkly at odds with that of the Prophet Muhammad and the early caliphs, disturbed many Muslims, which led to a number of revolts by various groups. One of these revolts was led by Husayn, ‘Ali’s son and the grandson of the Prophet Muhammad. When Husayn, who is revered by both Shi‘a and Sunnis alike, was brutally killed along with many of his family members by the Umayyads at Karbala in Iraq, this crystallized the belief among supporters of ‘Ali (Alids) that governance should have remained with the descendants of the Prophet Muhammad. Subsequent attempts to overthrow the Umayyads by another son of ‘Ali and by others such as ‘Abd Allah ibn al-Zubayr, a grandson of the first caliph Abu Bakr, were unsuccessful until the Abbasid revolution in 750. The Alids had supported the Abbasids, another branch of the Prophet’s family, believing the Abbasids would hand over rule to the Alid line. They were soon disappointed when the Abbasids claimed rule for themselves. In response, the Alids fomented a number of small and unsuccessful rebellions. Under increasing repression by the Abbasids, their political movement took on a more theological character.

The term Shi‘at ‘Ali or “the faction of ‘Ali” at some point became merely Shi‘a, while the term Sunni came to include those who agreed upon the validity of the rule of all of the first four caliphs. While today there are theological differences between these two major Muslim groups, they are in agreement on the cardinal points of faith and practice, and are both integral parts of the Islamic community (ummah).

Much of the conflict between Sunnis and Shi‘a is more political than religious. For instance, in Iraq before the Second Gulf War, Sunnis dominated Saddam Hussein’s regime. After the war, rule was shifted to the majority Shi‘i population, and this has produced tensions that have often been exploited by extremists on both sides.

Syria also illustrates the point. The Assad family, from the Alawite minority, ruled for decades over a Sunni majority with Iranian and Hezbollah backing, while Saudi Arabia and Turkey supported the opposition; an alignment that was fundamentally a contest between an entrenched dictatorship and its opponents. Bashar al-Assad fled in December 2024, and a transitional government under former opposition commander Ahmed al-Sharaa has been in place since. Sectarian violence has continued during the transition, including mass killings of Alawite civilians in early 2025 and clashes involving Sunnis and Druze communities in the south.

In Yemen, the Sunni-Shi‘i divide has likewise been one factor in a war driven principally by domestic power struggles, with Saudi Arabia and Iran backing opposing sides. In Bahrain, the Shi‘i majority has protested rule by a Sunni monarchy and faced repression as a result.

Shi‘i-Sunni conflict in Pakistan has its roots in the ruling party’s political exploitation of sectarianism to win the favor of Sunni religious authorities at the expense of the Shi‘i minority, who continue to suffer persecution.

While these conflicts are of concern to Muslim Americans who have family in the countries involved, sectarian conflict has rarely affected the larger Muslim American community, in part because Sunni and Shi‘i leaders in this country have made concerted efforts to prevent discord and demonstrate unity.

The starting points for Muslims are Quranic: “there is no compulsion in religion” (2:256), and the teaching that God deliberately created human beings different, “had God willed, He would have made you one community” (5:48), so that religious diversity is viewed as part of the divine plan, not a problem to be eliminated. The Quran recognizes that God sent messengers to every people, honors the prophets of Judaism and Christianity as Islam’s own, and holds that final judgment of every person, Muslims included, belongs to God alone.

Within that frame, Muslims, like Christians, hold a range of theological positions about other faiths, from those who believe that salvation is reserved for those who accept Islam to those who read verses such as “those who believe, and the Jews, Christians, and Sabians, whoever believes in God and the Last Day and does righteousness, will have their reward with their Lord” (2:62) as extending God’s promise more widely. Both camps cite scripture, and the debate parallels exclusivist-inclusivist debates among Christian theologians. What Islam does not leave open to debate is conduct: justice, kindness, and good neighborliness toward people of every faith and none are obligatory, and the Quran explicitly commands dealing kindly and justly with those who do not fight Muslims over their religion (60:8).

Contemporary Muslim scholarship has formally reaffirmed these principles at the highest level. The Amman Message (2004–2005), initiated in Jordan and unanimously endorsed by more than 500 leading scholars representing every major branch and school of Islam, recognized the validity of the different Islamic schools of law, Sunni and Shi’a alike, and forbade declaring fellow Muslims apostates, the practice of takfir that extremist groups use to license violence. The Marrakesh Declaration (2016), issued in Morocco by hundreds of Muslim scholars and leaders from over 120 countries in direct response to ISIS’s persecution of Christians and Yazidis, invoked the Prophet Muhammad’s own Charter of Medina, a seventh-century compact guaranteeing religious liberty to all its parties, to declare that religious minorities in Muslim-majority lands are entitled to full, equal citizenship. ING’s interfaith work rests on this ground.

“People of the Book” (Ahl al-Kitab) is the Quran’s term for communities who received earlier revealed scriptures, principally Jews and Christians, with some scholars extending it to Zoroastrians and others. The term itself is a statement of kinship: it groups Jews, Christians, and Muslims as fellow recipients of revelation from the same God through prophets Muslims also claim as their own, including Abraham, Moses, David, and Jesus. Islamic law gave the category practical weight: Muslims may eat the slaughtered meat of the People of the Book and marry women of these faiths, intimate forms of recognition not extended to other groups.

The Quran’s statements about them are deliberately differentiated, and reading them all matters. It praises some, “among the People of the Book is an upstanding community, reciting God’s verses through the night as they prostrate” (3:113), criticizes others for failing their own scriptures’ commands (as it criticizes Muslims for failing theirs), and disputes specific doctrines, most notably the Trinity, while commanding that argument with them be conducted “in the most courteous way” (29:46). In other words, the Quran models something contemporary interfaith relations still strive for: genuine theological disagreement inside a frame of recognized kinship. That frame helped to shape centuries in which Jewish and Christian communities lived, worshipped, and often flourished under Muslim rule, imperfectly by modern standards, as we discuss elsewhere, but in an era when religious minorities elsewhere fared far worse.

According to the Oxford English Dictionary, the English word “infidel” means “a person who does not believe in religion or who adheres to a religion other than one’s own.”

The Arabic word kafir is sometimes translated as “infidel.” A more common translation is “disbeliever” or “unbeliever.” In the Quran, kafir usually refers to a person who not only rejects the beliefs of Islam but also takes a hostile stance toward Muslims and their religion; it is used primarily to refer to the Meccans who rejected their kinsmen’s adoption of the new religion and persecuted and fought the growing Muslim community. In modern Arabic, kafir is often used to mean simply “non-Muslim,” without any negative connotation.

We strongly believe that people of other faiths should be treated with love and respect, affirming the Islamic principle of respect for freedom of religion and conscience. According to global Pew polls, strong majorities of Muslims in nearly every country surveyed support the right of non-Muslims to practice their religion freely, a right that was historically upheld by most Muslim societies.

The Quran contains passages critical of those who fought against the early Muslims, including some pagans, Christians, Jews, Arabs, and even hypocrites within the Muslim community. These passages speak to the specific historical circumstances in which they were revealed. They are not condemnations of Jews and Christians in general, but criticisms of the behavior of specific people, including, as noted, some Muslims.

We hold that respect for freedom of religion and conscience is basic to our vision of Islam.

Antisemitism originated as a modern European racial ideology, and it is not what these passages express: they are addressed to particular communities in a particular seventh-century dispute, and they criticize Muslims in the same breath. That said, some Muslims have read these verses as blanket condemnations, and antisemitic material does circulate in parts of the Muslim world, often borrowed wholesale from European sources. We regard that as a betrayal of Islamic teachings. ING, Muslim scholars, and Islamic institutions have condemned Holocaust denial and antisemitism. ING also treats opposing antisemitism as inseparable from opposing Islamophobia.

No, the Quran explicitly rules out compulsion in religion (2:256), commands justice and kindness toward those who do not fight Muslims over their faith (60:8) and describes religious pluralism as God’s design. The endurance of ancient churches, synagogues, and temples across the Muslim world, in Egypt, Turkey, Palestine, Jordan, Syria, India, and Bosnia, alongside communities that have worshipped in them continuously for fourteen centuries, is physical evidence that Muslim societies historically understood these commands as binding; minorities cannot survive fourteen hundred years of rule by people taught to hate them.

It is also important to address the historical arrangement critics often point to: the dhimma system, under which non-Muslims paid a tax (jizya) in lieu of military service and received protection and communal autonomy. Judged against its era, when religious minorities in Christendom faced expulsion, forced conversion, and pogroms, it was remarkably tolerant; judged against modern equal citizenship, it institutionalized subordinate status for non-Muslims. 

Contemporary Muslim scholarship has addressed this directly: the 2016 Marrakesh Declaration, issued by hundreds of leading scholars from over a hundred countries, grounds full and equal citizenship for religious minorities in the Quran and the Prophet’s Charter of Medina, declaring the old framework superseded by the nation-state compact all citizens share. Where non-Muslims face persecution in parts of the Muslim world today, and they do, Muslim scholars and organizations are on record condemning it, and ING regards defending religious minorities everywhere, including Christian minorities in Muslim countries, as a direct application of our principles.

Islamic teachings do not permit Muslims to force other people to become Muslims. The Quran explicitly states that “there is no compulsion in religion” (2:256), and religious diversity has existed in Muslim societies throughout Islamic history.

Muslim-ruled societies historically included substantial Christian, Jewish, Hindu, Buddhist, and other communities. Their treatment varied according to time and place, but the Islamic ideal of religious freedom was generally upheld by Muslim rulers throughout history. Forced conversions were rare and contrary to the teachings of the Quran and the Prophet Muhammad.

Today, Muslims hold diverse political and religious views, as do members of other faiths. We believe freedom of religion and conscience means that people must be free to practice Islam, another religion, or no religion without coercion. For Muslim Americans, this principle is also protected by the First Amendment, which guarantees the free exercise of religion and prohibits the government from establishing a religion.

Yes, in a specific sense: Muslims believe God revealed scriptures before the Quran, the Scrolls of Abraham, the Torah of Moses, the Psalms of David, and the Gospel of Jesus, and belief in these prior revelations is one of Islam’s six articles of faith. The Quran calls itself a confirmation of what came before. Muslims also generally maintain that those scriptures, as transmitted, no longer perfectly preserve the original revelations, which is why Muslims follow the Quran where accounts differ.

The nuance worth adding is that Muslim scholars have understood this “alteration” (tahrif) in different ways: some as changes to the texts themselves over centuries of transmission, others primarily as misinterpretation of texts that remain substantially intact, and classical scholars in the second camp cited the Bible respectfully in their own works. In practice, Muslims treat Bibles with respect as containing revelation and revere the figures within them. Many Muslims read the Bible with interest, and Muslim-Jewish and Muslim-Christian scriptural study groups (“scriptural reasoning”) have become a fruitful form of American interfaith engagement. What a Muslim will not do is treat any earlier scripture as superseding the Quran, precisely the mirror image of how Christians read the Hebrew Bible through the New Testament, a structure Jews and Christians will recognize from their own relationship.

Although the Buddha was not mentioned among the twenty-five prophets named in the Quran, some Muslim scholars suggest that, because of the high moral standards he advocated, including compassion to help alleviate the suffering of all beings, the Buddha may have been among the unnamed prophets whom, the Quran proclaims, God sent to every nation. The same may have been true of founders or major figures in other religious traditions.

More closely, and on more issues, than headlines suggest. Israel and Palestine dominate public perception of the relationship, but they do not define it; and perhaps the most important thing to understand is that Muslim-Jewish cooperation in America has never required agreement on the Middle East. Jews and Muslims are already colleagues, neighbors, classmates, healthcare professionals, and civic leaders working side by side, and their organized collaboration spans a remarkable range.

Some of it does concern the conflict itself: Jewish, Muslim, Christian, and secular activists work in coalitions advocating for Palestinian human rights, humanitarian aid, and political solutions, genuinely multireligious activism rather than “Muslim activism” alone. But much of the collaboration lies elsewhere. Muslims and Jews work together against both antisemitism and Islamophobia, treating the two hatreds as linked rather than competing concerns, through educational programs like ING’s own combined antisemitism-Islamophobia trainings, through interfaith policy coalitions, and through major philanthropic commitments such as the Open Society Foundations’ 2026 announcement of $30 million to strengthen efforts against both forms of hate. They have collaborated for years on civil rights and religious freedom: hate-crime legislation, protection of houses of worship, workplace religious accommodations, and minority rights, the shared concerns around which the Muslim-Jewish Advisory Council, convened by the American Jewish Committee and the Islamic Society of North America, was explicitly founded. Jewish organizations regularly partner with Muslim ones on refugee resettlement; ING’s own office routinely receives calls from Jewish agencies seeking services for resettling Muslim refugees. Mosques, synagogues, and interfaith groups run joint food drives, soup kitchens, and homeless services, in ING’s own Bay Area, Abrahamic Alliance International brings Muslim, Jewish, and Christian volunteers together to prepare and serve free meals while deliberately building relationships across communities, and has hosted classes on Judaism at a local mosque. Muslim and Jewish women have built especially strong networks of friendship, leadership, and service, with the Sisterhood of Salaam Shalom being the best-known example. And communities simply learn from one another: visiting each other’s mosques and synagogues, sharing Ramadan iftars and Passover Seders, including synagogues hosting iftars precisely to sustain relationships during periods of Middle East tension.

None of this means the relationship is untested. Since October 7, 2023, and the Gaza war, many relationships have been strained, and both communities have simultaneously faced surging hate. That is exactly why organizations like NewGround: A Muslim-Jewish Partnership for Change matter. They exist specifically to build relationships resilient enough for difficult conversations across profound disagreement. The strain is real; so is the infrastructure of friendship built over decades to withstand it.