Why Islam is Not Compatible with Christianity or Judaism

Introduction

Islam is often presented as one of the “three Abrahamic faiths,” alongside Christianity and Judaism, implying that all three share a common theological foundation. While it is true that Islam acknowledges figures like Abraham, Moses, and David, its doctrines ultimately redefine these biblical figures and alter their messages in ways that cannot be reconciled with the Bible.

For Christians, the most critical point of departure is Islam’s rejection of Jesus Christ as God and Savior. For Jews, Islam’s rewriting of Israel’s history and covenant identity is equally irreconcilable.

1. The Nature of God

Islam’s Teaching:

Islam teaches that Allah is strictly singular and that any association of partners with Him is “shirk” (the greatest sin in Islam). The Qur’an explicitly rejects the Trinity (Surah 4:171; 5:73), viewing it as polytheism.

Biblical Teaching:

The God of the Bible is One, but revealed in three Persons—Father, Son, and Holy Spirit (Deuteronomy 6:4; Matthew 28:19; 2 Corinthians 13:14). The Trinity is not three gods, but one God in three co-eternal Persons.

Why They’re Incompatible:

Denying the Triune nature of God is not a small theological disagreement—it directly contradicts the self-revelation of God in Scripture. Christianity without the Trinity is not biblical Christianity.

2. The Identity of Jesus

Islam’s Teaching:

Jesus (ʿIsa) is considered one of the greatest prophets, born of the virgin Mary, but not the Son of God. Islam denies His crucifixion, teaching instead that He was not killed but taken up to heaven (Surah 4:157–158). In Islamic eschatology, Jesus will return to break the cross, kill swine, and establish Islamic law.

Biblical Teaching:

Jesus is the eternal Word made flesh (John 1:1, 14). He died for the sins of the world and rose again bodily (1 Corinthians 15:3–4). Jesus openly declared His divinity: “Before Abraham was, I am” (John 8:58) and “I and the Father are one” (John 10:30). His return will be to judge the nations and reign as King of Kings—not to enforce Sharia law.

Why They’re Incompatible:

Islam’s version of Jesus is a rewritten figure who bears little resemblance to the biblical Jesus. Denying His death and resurrection is a denial of the gospel itself (1 Corinthians 15:17).

3. The Authority of Scripture

Islam’s Teaching:

Islam claims the Torah and the Gospel were originally from God but have been corrupted (tahrif). Therefore, the Qur’an is seen as the final, perfect revelation.

Biblical Teaching:

The Old and New Testaments are God-breathed, preserved, and unchanging (Psalm 119:89; Matthew 24:35; 2 Timothy 3:16). Jesus affirmed the authority of the Law, the Prophets, and the Psalms (Luke 24:44).

Why They’re Incompatible:

If the Bible is corrupted, then Jesus’ own affirmation of it would be false—which undermines both Christianity and Judaism. Conversely, if the Bible is true, then the Qur’an’s claims against it cannot be.

4. The Covenant People of God

Islam’s Teaching:

Islam teaches that the promises made to Abraham’s descendants belong to Ishmael’s line, not Isaac’s. This reassigns the covenant blessings and portrays Israel’s biblical history as altered.

Biblical Teaching:

God’s covenant was made with Isaac, not Ishmael (Genesis 17:19–21). The promises to Israel are eternal (Jeremiah 31:35–37; Romans 11:1–2).

Why They’re Incompatible:

The Qur’an’s version of history directly contradicts the biblical record and undermines the covenant identity of Israel, which is foundational to both Judaism and Christianity.

5. Salvation

Islam’s Teaching:

Salvation is earned through submission to Allah, good works, and following the Five Pillars of Islam. There is no assurance of eternal life, except for martyrs in jihad.

Biblical Teaching:

Salvation is by grace through faith in Jesus Christ alone—not by works (Ephesians 2:8–9; Titus 3:5). Believers are sealed with the Holy Spirit and assured of eternal life (John 10:28).

Why They’re Incompatible:

The gospel message is centered on what Christ has done, not what man can do. Islam’s works-based salvation is fundamentally opposed to the biblical way of salvation.

6. The Role of Muhammad

Islam’s Teaching:

Muhammad is the “seal of the prophets,” and no prophet or revelation can come after him except in the form he delivered.

Biblical Teaching:

The Bible gives no prophecy of Muhammad. In fact, Hebrews 1:1–2 teaches that God’s final revelation came through His Son, Jesus Christ—not another prophet.

Why They’re Incompatible:

Acknowledging Muhammad’s authority requires rejecting Jesus as the ultimate and final revelation of God.

Conclusion

Islam and Christianity (and likewise Judaism) are not simply different “expressions” of the same faith—they are built on contradictory foundations. While Islam borrows names and stories from the Bible, it reinterprets them in ways that reject the very truths that define biblical faith.

Christians are called to love Muslims as individuals, to share the truth with gentleness and respect (1 Peter 3:15), but also to be clear that the gospel of Jesus Christ cannot be merged with the message of Islam.