Theology of Religions: Islam

Introduction

In an increasingly pluralistic and religiously diverse world, Christians are continually challenged to understand, articulate, and defend their faith in the face of competing worldviews. While Christianity remains the world's largest religion, one of the most significant and widespread religious systems that confronts biblical Christianity today is Islam, which has quickly become the second largest religion, claiming over a billion adherents. Islam shares certain similarities with Christianity, such as belief in one God, prophetic revelation, and moral accountability; however, it diverges profoundly in its view of God, Scripture, salvation, and the person and work of Jesus Christ. These differences are not merely peripheral but strike at the very heart of the Christian gospel. Moreover, it holds significant influence in the religious and cultural dynamics of the globe. In the United States, the number of individuals who identify as Muslim has increased in recent years, which is why Christians must possess a clear understanding of Islamic beliefs, practices, and history to faithfully and thoughtfully engage with Muslims. The evangelistic efforts of Christians, however, must be rooted in the exclusivity of Christ and the Gospel despite having to be practiced in an increasingly pluralistic society where all religions are seen as equally valid.

This paper aims to provide a biblically grounded, Reformed analysis of Islam by exploring its origins, doctrines, and worldview while contrasting them with the exclusive claims of Christianity. From a Reformed theological perspective, which emphasizes the sovereignty of God, the total depravity of humanity, and salvation by grace through faith in Christ alone, Islam presents a theological system that ultimately denies the sufficiency and supremacy of Jesus Christ. Such a comparison is not merely academic but deeply pastoral and evangelistic in nature. As believers are called to engage with Muslims in truth and love, a faithful understanding of Islam is necessary for proclaiming the gospel effectively. Drawing upon key theological and apologetic works, this paper will evaluate Islam's fundamental claims and examine how they differ from the redemptive message found solely in Christ. Ultimately, the goal is to uphold the uniqueness and finality of Jesus Christ as the only way to God, as affirmed in John 14:6, while equipping believers to witness with clarity, conviction, and compassion.

Overview of Islam

In its most basic sense, Islam is a monotheistic religion that arose in the 7th century CE in the Arabian Peninsula. It teaches submission to Allah, the Arabic word for God, and is centered around the revelations given to Muhammad, believed by Muslims to be the final prophet. The primary sacred text in Islam is the Qur'an, considered the literal word of God dictated to Muhammad by the angel Jibril (i.e., Gabriel). An additional text held in high regard by Muslims is the Hadith, which is a collection of sayings and actions of Muhammad that play a significant role in shaping Islamic law and practice. Essentially, the religion is structured around the Five Pillars: Shahada (confession of faith), Salah (ritual prayer), Zakat (almsgiving), Sawm (fasting during Ramadan), and Hajj (pilgrimage to Mecca). These practices form the core of Islamic devotion. The call to prayer punctuates daily life, and communal observances like Ramadan shape entire communities. Also, Islamic dress codes, dietary laws (i.e., halal), and etiquette are all governed by a desire to submit fully to the will of Allah. Moreover, Muslims also affirm six articles of faith, which are belief in Allah, angels, revealed books, prophets, the Day of Judgment, and divine predestination. While there are many sects within Islam, the two largest branches are Sunni and Shia. More specifically, Sunni Muslims constitute the majority while Shia Islam is dominant in regions like Iran and parts of Iraq.

Beyond theological tenets, Islam serves as a total worldview encompassing religious, legal, social, and political aspects of life. Sharia, or Islamic law, influences the daily behavior of adherent and varies in interpretation across different cultures and countries. Education in Islamic history and jurisprudence is often promoted from an early age in Muslim-majority countries. Additionally, Islam's heavy emphasis on community and ummah (i.e., global brotherhood) fosters a strong sense of solidarity among Muslims worldwide. This collective identity plays a vital role in shaping Muslim consciousness, encouraging solidarity, mutual responsibility, and the implementation of Islamic principles in both personal and communal life. The annual pilgrimage to Mecca (i.e., Hajj), which draws millions from around the world, visually manifests this global unity and religious devotion. Additionally, Islamic dress codes, dietary laws, and common greeting rituals, such as "As-salamu alaykum" reinforce this shared identity across cultures. In many Muslim-majority societies, Islamic values are embedded in education, law, and public policy, further demonstrating Islam's holistic vision for human life. For Muslims, faith is not a private affair, but rather a comprehensive worldview that informs every aspect of existence, from family life to social ethics to economics and governance.

Furthermore, Islam positions itself as the final and complete revelation from God, communicated through the prophet Muhammad and preserved in the Qur'an. Muslims believe that previous scriptures, such as the Torah (i.e., Tawrat), Psalms (i.e., Zabur), and the Gospels (i.e., Injil), were initially divine revelations given to prophets like Moses, David, and Jesus; however, Islam teaches that these earlier texts were subsequently altered or corrupted by human hands. Thus, they lost their original purity and authority. While Muslims hold biblical figures like Abraham, Moses, and Jesus in high regard as true prophets of God, they firmly reject the central doctrines of Christianity, including the Trinity, the deity of Christ, and the atoning death and resurrection of Jesus. The Islamic view asserts that Jesus was a prophet but not divine, and that he was neither crucified nor resurrected. This perspective shapes Islamic apologetics and dialogue with Christians, as Muslims often seek to affirm continuity with biblical tradition while simultaneously denying the heart of the Christian faith. Lastly, historically speaking, Islam spread through military conquest, diplomacy, and trade, which helped entrench it in diverse cultural contexts from North Africa to Southeast Asia. It is important, especially for Christians, to understand this multifaceted nature of Islam because it enables believers to engage with Muslims in a compassionate and truthful manner.

Founder, History, Doctrines, and Tenets

According to Islamic tradition, Muhammad is the religion's founder, and he was born in Mecca in 570 CE. Orphaned at a young age, he grew up under the care of his uncle and became a merchant known for his integrity. Supposedly, he began receiving divine revelations from Allah at the age of forty. These revelations continued for approximately 23 years, and they were later compiled into the Qur'an, Islam's primary holy book. Muhammad's teachings were initially rejected by many in Mecca as they challenged the polytheism of the culture. The rejection of his ideas led to severe persecution, so he was prompted to migrate to Medina in 622 CE, and this journey was known as the Hijrah. Interestingly, this migration was a pivotal event that marked the beginning of the Islamic calendar. In Medina, he became both a spiritual and political leader. Following Muhammad's death in 632 A.D., Islam spread rapidly through military conquest, missionary efforts, and trade across the Arabian Peninsula, North Africa, the Iberian Peninsula, and parts of Asia. The caliphates that followed played significant roles in shaping Islamic theology, law, and culture. The first four caliphs are especially revered in Sunni Islam, while the Shia tradition traces authority through the imams descended from Ali.

Doctrinally speaking, Islam's theology is staunchly monotheistic, meaning Allah is one without partners, children, or equals. This belief directly contradicts the Christian doctrine of the Trinity; however, the differences between Christianity and Islam will be discussed later. Furthermore, Islam acknowledges many prophets, including at least five from the Bible. More specifically, Islam recognizes Adam, Noah, Abraham, Moses, and Jesus, but the religion insists that Muhammad is the final and greatest prophet. This doctrine is recognized in the "Seal of the Prophets." Based on this Islamic belief, it is clear that Muslims deny the divinity of Christ, which leads them to also deny His crucifixion and resurrection. Interestingly, Jesus is seen as a prophet born of the virgin Mary and a servant of Allah; however, he is not the Son of God who provided the only path to salvation. According to Costa, Islam's portrayal of Jesus is a, "...deliberate rejection of the Christian faith's central claims about Him, particularly His deity and salvific work." Additionally, Islam also espouses a works-based soteriology, meaning salvation is not assured but dependent on the mercy of Allah and one's obedience to Islamic law (i.e., Sharia). Unlike Christianity's emphasis on grace, Islam lacks a robust understanding of human depravity and divine atonement.

Beyond theology, Islam is also a comprehensive way of life. More specifically, Sharia governs religious, civil, and criminal law. As mentioned above, practices such as modest dress, dietary restrictions, and gender roles are deeply embedded in Muslim communities. Furthermore, mosques serve not just as places of worship but as centers of social and political activity. The daily life of a devout Muslim is saturated with rituals and reminders of submission. Whether through the repetition of divine names, the structured discipline of prayer, or the abstinence during Ramadan, these practices instill a God-consciousness that permeates family, work, and community. Sharia law offers further guidance on social interactions, ethical decisions, and legal disputes, aiming to create a society that reflects divine justice and order. In this way, Islam presents not merely a religion but a comprehensive theocratic system that governs every aspect of human existence. While there are noble ethical aspirations in Islamic law, these are framed around external observance rather than inward regeneration. This contrast will become particularly important when evaluating the gospel's power to transform the human heart through union with Christ.

The Exclusivity of Christ

Despite superficial similarities, such as monotheism, reverence for prophets, and ethical codes, Islam and Christianity differ fundamentally in their understanding of God, original sin, humanity, and salvation. For instance, Islam's view of God (i.e., Allah) emphasizes absolute transcendence and unity (i.e., Tawhid), leaving no room for the Trinitarian doctrine that is foundational to Christianity. As Erickson observes, "A denial of the Trinity is a denial of the very heart of Christian theology." Furthermore, one of the most crucial areas of divergence is the identity and mission of Jesus. In Islam, Jesis is honored as a prophet but not divine, and certainly not crucified or resurrected. More specifically, the Qur'an explicitly denies the crucifixion of Christ, which is a central tenet of the Christian faith. As Costa explains, "Islam relegates Jesus to a secondary status and strips Him of the redemptive work accomplished on the cross." Ultimately, the denial of Christ's deity has profound theological consequences. The Christian gospel is that humanity, corrupted by sin, cannot attain righteousness through works but only through the atoning death and resurrection of Jesus Christ. As Grudem emphasizes, "Justification is a legal declaration by God that we are not guilty but righteous in His sight because of Christ." By contrast, Islam offers no assurance of salvation, but rather it emphasizes works and the mercy of Alla; however, it lacks a mediator who fully satisfies divine justice. As Pikkert notes, "Islam's hope lies in a scale of deeds, whereas Christianity offers substitutionary atonement."

In essence, this contrast illustrates the unique and exclusive nature of the gospel. As Jesus declares in John 14:6, "I am the way, the truth, and the life; no one comes to the Father except through me." The exclusivity of Christ is not arrogance, but truth grounded in His divine identity and saving work. Therefore, Christians ought never to compromise on the truth of the gospel for it is the only means of salvation for mankind. God commands believers to love their neighbor, but Christians cannot properly love their neighbor if they fail to share the gospel with them despite their adherence to other religions. As Netland writes, "If Jesus is who Christians affirm him to be, then commitment to Him must be exclusive." Moreover, Christianity offers a radically different vision of transformation. While Islam provides moral guidance and community discipline, it lacks the inner renewal that comes through the indwelling Holy Spirit. For example, Miles points out that Christianity, "...offers the transforming power of the resurrected Christ, something no other religion can replicate." It is this indwelling presence that brings new affections, sanctifies the believer, and provides the hope of glorification, which is a holistic redemption that Islam does not, and cannot, promise.

Therefore, Christian apologetics must uphold, and preach, the uniqueness of Christ with humility, courage, and boldness. Craig argues, "...the resurrection of Jesus is the cornerstone of the Christian worldview and offers objective grounds for faith." The historical reliability of the resurrection, supported by sources like Jeremiah Johnston's book, Body of Proof: The 7 Best Reasons to Believe in the Resurrection of Jesus, provides compelling evidence that Christianity alone offers a Savior who has conquered death and secured eternal life. Johnston affirms the cumulative case for the resurrection through multiple lines of evidence, such as the empty tomb, eyewitness testimony, and the transformation of the disciples. He highlights that skeptics like James, the brother of Jesus, and Saul of Tarsus became ardent followers after post-resurrection appearances. Additionally, Johnston defends the integrity of early Christian creeds embedded in 1 Corinthians 15:3-5, demonstrating their proximity to the events they describe. These facts do not make the resurrection a myth, but rather a historically grounded truth that demands a response. Thus, Islam's denial of these events cannot account for the explosive growth of the early Church or the willingness of Jesus' followers to suffer and die for what they claimed to have seen. While Islam claims continuity with biblical revelation, it diverges at every crucial point where Christianity affirms the uniqueness and supremacy of Christ. In rejecting Jesus' divine identity, atoning death, and resurrection, Islam offers no sufficient basis for salvation. As Martin rightly classifies in his book, The Kingdom of the Cults, Islam, despite its moral rigor and theological sophistication, ultimately denies the core essential of the gospel.

Conclusion

Understanding Islam from a biblical and Reformed perspective requires clarity, conviction, and compassion. Islam presents a comprehensive worldview with its own sacred texts, practices, and vision for human life; however, when compared to the gospel of Jesus Christ, it lacks the saving power found only in the risen Savior. The founder of Islam, Muhammad, claimed to deliver God's final revelation, but his teachings stand in direct opposition to the gospel. While Muslims revere Jesus as a prophet, they deny His crucifixion, resurrection, and divine Sonship, the very foundation of the Christian faith. Therefore, Christians must engage with Muslims by speaking the truth in love, seeking opportunities to share the gospel while respecting their dignity as image-bearers of God. Apologetic efforts must point to the uniqueness of Christ, supported by historical evidence the testimony of Scripture. As Erickson and Grudem both affirm, the triune God has revealed Himself fully in Christ, and salvation comes through Him alone. In an age of increasing religious pluralism, the church must not compromise on the exclusivity of Christ.