In the West the Qur’an has long been understood as the work of Muhammad, a religious reformer in the pagan world of seventh-century Arabia. Muhammad’s Arabia, it is commonly explained, was a land where the Bible was hardly known, even if it had become a refuge for Jewish and Christian heretics fleeing from the Byzantine Church.

Non-Muslims have often assumed that such heretics are the source of the biblical material in the Qur’an. The eighth-century Christian writer John of Damascus, for instance, insists that Muhammad wrote the Qur’an with the help of an Arian monk and “spread rumors of a scripture brought down to him from heaven.” Scholars today tend to avoid the question of the Qur’an’s authorship, but they continue to describe the Qur’an according to old notions of Muhammad’s life and Muhammad’s Arabia.

For their part, Muslims insist that the Qur’an is in any case not the work of Muhammad. The Qur’an, they say, was brought down from heaven to Muhammad by the angel Gabriel. Muhammad merely pronounced what the angel Gabriel recited to him. He was something like a statue in a fountain through which the divine water of revelation flowed, pure and unchanged.

And yet Muslims also believe that the Qur’an was, in a fundamental way, revealed for Muhammad: God sent down individual pieces of the Qur’an whenever the Prophet needed guidance. In this way Muslims explain a celebrated passage on sexual relations in the Qur’an’s second chapter, which instructs (male) believers: “Your women are your field. Go into your field as you wish.” The agricultural metaphor is clear enough, but a historical context for this passage is provided by Islamic tradition. In the words of a modern Muslim interpreter: “When the Muslims migrated from Mecca the men found the women of Medina bashful and only willing to sleep with their husbands lying on their side. So the Muslim men asked the Prophet if there was anything wrong with such sexual positions.”

As it happens, the Qur’an has nothing to say about the bashfulness of women in Medina, the city to which Muhammad is said to have emigrated in the year 622. Yet Muslim scholars insist that such stories come from Muhammad’s own companions—and that this body of tradition, known collectively as hadith , is a reliable guide to understanding the Qur’an. Through such stories, Islamic tradition turns the Qur’an into a book about Muhammad.

Western scholars, for the most part, also accept these stories, even if they do not believe that the angel Gabriel brought messages to Muhammad from heaven. They may reject hadith that smack of legends—such as the Prophet’s journey to Jerusalem on a magical winged horse. But there is nothing particularly legendary about the story of the bashful women of Medina. Anyway, it’s all that scholars have to go on. Outside of Islamic tradition there is no record of the historical context in which the Qur’an was proclaimed.

And yet there is a serious scholarly problem with relying on these traditional stories about Muhammad. The Qur’an was presumably proclaimed before 632, the traditional date of the Prophet’s death. Yet the stories about Muhammad first appear in books written around 800—when the center of the Islamic empire was neither Mecca nor Medina but Baghdad.

Muslims—and many non-Muslim Western scholars—insist that the stories about Muhammad and the Qur’an were passed down through a reliable oral tradition. And yet not infrequently these stories appear impossible, not because they seem fantastic or legendary but rather because they betray a poor understanding of the text.

In the fourth chapter, for example, the Qur’an accuses Jews of various offenses: breaking their covenant, disbelieving the signs of God, killing the prophets, and saying “Our hearts are covered.” Most Muslim commentators explain this final accusation by noting that, when Muhammad arrived in Medina, the Jews there stubbornly refused to accept his claims of prophethood, saying to him, “Our hearts are covered from everything you are saying. We will not listen to you.”

Yet the Arabic word for covered (ghulf) here means, more precisely, “uncircumcised.” In other words, the Qur’an is employing Jeremiah’s famous metaphor of an uncircumcised heart, which, in the New Testament, both Luke and Paul direct against the Jews. Muslim commentators, having little interest in or knowledge of the Bible, miss the metaphor.

The story of the Jews in Medina with the covered hearts, in other words, appears not to be history but what would be called, in the Jewish context, haggadic exegesis: a narrative written in order to explain ­scripture. In this case the exegetical nature of the story is recognizable because of the biblical metaphor. But what about other cases, such as the story of the bashful women? Did Muslims really remember how Muhammad counseled the faithful on marital relations, or did exegetes write a story about Muhammad to explain an ambiguous verse? To what degree is the relation between Muhammad and the Qur’an generally the creation of Muslim exegesis?

The question is troubling, and even more so when we observe how little the Qur’an itself has to say about Muhammad. The Qur’an names Moses 136 times, Abraham 69 times, Jesus 25 times, but Muhammad only 4 times. It provides no detailed information about his home, his wives, his children, his friends, or his enemies. Indeed, the Qur’an provides essentially no biographical information on Muhammad, unless it is read through the stories in Islamic exegesis.

Nonetheless, most scholars rely on these stories to explain the Qur’an. In Chapter 111, for example, the Qur’an refers to “The Father of Flame,” who will not benefit from his money but “roast in a burning fire,” and his wife, “who carries firewood and has a fiber rope around her neck.” Karen Armstrong (a former nun and popular writer on Islam) explains, “Abu Lahab’s wife, who fancied herself as a poet, liked to shout insulting verses at the Prophet when he passed by. On one occasion she hurled an armful of prickly firewood in his path.”

Armstrong relies on Muslim traditions that make Abu Lahab’s wife historical, but without these traditions the chapter would seem to be an artful metaphor of a foolish rich man and his wife who carries the wood that will fuel her own punishment in hell. Instead, we are given historical claims of a Meccan woman who attacked Muhammad by hurling firewood (Armstrong invents the prickly part) at him.

This sort of approach is still the dominant one, though a minority of researchers have begun to follow the scholar John Wansbrough in a new direction. In his 1977 book Qur’anic Studies, Wansbrough argues that the Qur’an was written in a Judeo-Christian context. The Islamic story of the Qur’an’s proclamation in the pagan, desert environment of Arabia was written to defend the claim that the new religion was revealed by God, not borrowed from Jews and Christians, and to develop a direct genealogical connection to Abraham (through Ishmael, who fled into the desert with his mother Hagar).

In their work Hagarism, published the same year, Wansbrough’s students Patricia Crone and Michael Cook went a step further, writing a history based exclusively on non-Islamic sources (which are, in fact, older than the Islamic sources). Islam emerged, Crone and Cook argue, when Arabs were informed of their Abrahamic ancestry by the Jews. Together Jews and Arabs reclaimed Jerusalem (and Hebron) from the polytheistic (or at least tritheistic) Byzantine Christians. The true emigration of the believers was not from Mecca to Medina but from the desert to the Holy Land.

Few scholars were convinced by the book (Cook himself is now among its skeptics), but Wansbrough’s approach continues to inspire new theories. The conviction that the Qur’an was proclaimed in a Judeo-Christian context lies behind such controversial works as the pseudonymous Christoph Luxenberg’s The Syro-Aramaic Reading of the Koran, first published in 2000.

Luxenberg’s best-known argument involves the qur’anic term hur, which Islamic tradition understands as a reference to virgins awaiting the believers in the garden of paradise. By one account, Muhammad described the hur as fabulous women with faces shining with divine light, who have the name of God inscribed on one breast and the name of the believer for whom they are destined on the other. Luxenberg argues that the word hur, which literally means “white,” refers instead to crystal-clear grapes. It is, he concludes, a reflection of the Syriac-Christian tradition of heaven as a garden—and thus the heavenly reward of the believers is not sex but fruit.

Some scholars find Luxenberg’s work to be cavalier and wrongheaded. At a conference I recently attended in Berlin, one respected German professor stood up and lamented that some scholars today act as though the Qur’an was revealed in Antioch and Jerusalem, not Mecca and Medina. Others, however, claim that Luxenberg’s book is momentous, since it undermines the notion that Islamic tradition preserves the ancient meaning of the Qur’an. Robert Phenix and Cornelia Horn conclude, “The future of qur’anic studies is more or less decided by this work.”

The question at hand, then, is about the reliability of Islamic tradition. To those influenced by Wansbrough, the dominant scholarship in Islamic studies, based firmly on the historical narrative of Islamic tradition, is not scholarship at all. In Patricia Crone’s words, most Western works on the Qur’an are nothing but “Muslim chronicles in modern languages and graced with modern titles.”

The result, as Angelika Neuwirth observes, is that qur’anic studies today have become “a hopeless chaos.” Neuwirth argues that the best way forward is sober, scholarly work on qur’anic manuscripts. Accordingly she has begun a major project—called Corpus Coranicum—to prepare the first critical edition of the Qur’an. The standard version of the Qur’an in use today, the “Cairo text,” was first published in 1924 by a committee appointed by the Egyptian government to establish a uniform Qur’an for the public-school system. The Egyptian committee published the result (and had variant texts sunk in the Nile River) without looking at a single old manuscript of the Qur’an.

Work done with the manuscripts will necessarily challenge the notion prevalent among Muslims that the Qur’an we read today is a perfect transcript of Gabriel’s recitation to Muhammad. As the apologetical website IslamBasics.com proclaims: “The doubters of the world are challenged to produce a Book like it and have produced none. It is the only revealed Book whose text stands pure and uncorrupted today, after 1,400 years!”

Still, the manuscripts that have come to light tell us very little. They are written in a simplified form of Arabic, lacking all vowels and many consonants. They contain no added verses, let alone chapters. The more compelling question is that of the origins of the Qur’an. Is the book, as Islamic tradition holds, intertwined with the biography of Muhammad? Or is it a work that emerges from the heart of the Judeo-Christian tradition? The reference to the uncircumcised heart mentioned above is one case that suggests this latter possibility should be taken seriously.

Another case is the Qur’an’s reference to the laughter of Sarah (a name that does not appear in the text; the only woman given a name in the Qur’an is Mary). In Genesis, Sarah laughs after she hears the annunciation of Isaac’s birth, but the Qur’an refers to her laughter first. Accordingly, Muslim commentators struggle to explain why she laughed. One famous commentator, the tenth-century al-Tabari, wonders if she laughed out of frustration when the visitors would not eat the food she prepared or if she laughed out of relief when she realized that the visitors did not have the habits of the Sodomites. Yet the reader who knows the Bible will understand that Sarah laughed out of surprise at the promise of a son in her old age, even if the Qur’an—for the sake of a rhyme in Arabic—reports these events in reverse order.

In such cases the Qur’an seems to count on its audience’s knowledge of the Bible. Indeed, by taking a liberty with the order of the story, the Qur’an seems utterly confident in that knowledge. It expects that the reader has the Qur’an in one hand and the Bible in the other.

I do not mean to suggest that the Qur’an is a Christian book, as Paul of Antioch, the twelfth-century bishop of Sidon, thought. He argued that when the Qur’an begins each chapter with the invocation “In the name of God, the Merciful, the Benevolent” it means “In the name of the Father, the Son, and the Holy Spirit.” Some theologians today continue to hold this notion. Giuglio Bassetti-Sani, a Franciscan missionary and author of The Koran in the Light of Christ, and Georges Tartar, a Protestant missionary and author of the similarly titled Connaître Jesus Christ: Lire le Coran la lumière de l’Évangile, both argue that the Qur’an, properly understood, is Christian. But it takes heroic effort to get that understanding from the Qur’an, a text that explicitly denies that Jesus is the son of God.

In any case, it is more common for Christians to separate the Qur’an from the Bible entirely. The early twentieth-century American Protestant missionary Samuel Zwemer comments, “In the Book of Job alone there are more glorious descriptions of God’s personality, unity, power, and holiness than in all the chapters of the Qur’an.” The popular Christian website ChristianAnswers.net prominently displays the slogan, “The differences between the Qur’an and the Bible are massive, beginning with the foundational history of Genesis, upon which the gospel is squarely based.”

With such rhetoric, Christian missionaries echo the efforts of Muslims throughout the centuries to separate the Qur’an from the Bible. Indeed, Muslims today generally consider the Bible to be a hopelessly misleading, if not dangerous, book. If Christians include the Jewish Scriptures in their own Bible, and Latter-day Saints believers put the Christian Bible on the shelf next to the Book of Mormon, Muslims usually have no place at all for the Bible. The Bible is to be read only when it is to be refuted. As a mufti on the popular religious website IslamOnline.net comments, “As for reading the Bible, if it is meant for answering questions of Christians, then it is OK.”

The Qur’an itself has a more generous attitude toward the Bible. If its religious message is not Christian, it hardly rejects the Christian Scripture. At one point it even asks that “the people of the gospel direct themselves according to what God has revealed in it.” The Qur’an, apparently, was not written to replace or correct the Bible. It was written to offer its own interpretation of the Bible.

Of course, both Christians and Muslims will agree that there are serious differences between the teachings of the two scriptures, especially when it comes to Christology. The Qur’an, committed to the absolute transcendence of God, insists that he could have no son. Yet the Qur’an’s rhetoric on this point is always directed against Christian teaching, not against the Bible. Thus in rejecting the notion of a divine son the Qur’an tells the Christians, “Do not go to excesses in your religion!” It does not tell them, here or anywhere else, to stop reading the Bible.

A Christian might respond that the idea of divine sonship is explicit in the New Testament and hardly a product of Christian interpretation. But what seems explicit to Christians may not seem so to others. The cases of gnosticism, Manicheanism, Mormonism, and Baha’ism (not to mention the imaginative Christian theologies in vogue today) show the Bible to be a flexible document.

In any case, the Qur’an exhibits both a familiarity with and an amicability toward the Bible. It is not the record of confused proclamations in a barbarous context where the Bible was barely known. Instead, the Qur’an emerged in a late-antique religious context where Jews and various Christian sects were arguing over the Bible’s proper interpretation. When delivering its religious message, the Qur’an counted on its audience’s knowledge of the Bible, and it continues to do so today.

Muslims, then, should read the Bible not only when they want to answer the questions of Christians but also when they want to answer their own questions about the Qur’an. So too Jews and Christians should learn to appreciate the intimate relationship between the Bible and the Qur’an, a text that should be recognized as part of the biblical tradition in universities and seminaries alike.

Gabriel Said Reynolds is the Tisch Family Associate Professor of Theology at the University of Notre Dame.