Galatians 1:6-9
"I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel, not that there is another one, but there are some who trouble you and want to distort the gospel of Christ. But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed. As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed."
"And no wonder, for Satan himself masquerades as an angel of light."
(2 Corinthians 11:14)
Recorded in the Hadith (a collection of Bukhari and Muslim writings), is a tradition that says Muhammad was first visited in the cave of Hira by a spiritual being who identified himself as the angel Gabriel who shared with him revelations that would become the Qur’an over the next 23 years.
These "revelations" explicitly contradict core elements of the apostolic gospel. In other words, the message delivered by this "angel" is a different gospel, precisely the scenario Paul warns against in Galatians 1.
Key among these different revelations was the very Gnostic idea that Jesus is not the divine Son of God. That God is spirit and therefore could not have come into humanity, he could not take on human form with all its gross and cruel natures.
The most reliable Islamic sources (Sahih al-Bukhari 1.1.3 and Sahih Muslim 1.301) describe Muhammad’s first revelation in the cave of Hira happening at around 610 AD. Six centuries after the gospel period. Muhammad encounters an angelic-like being. The encounter was terrifying; Muhammad was squeezed forcefully three times and commanded to "Recite!"
He fled in fear.
He initially believed he might have been possessed by a jinn or demon. He should have followed his first instincts.
His wife Khadījah and her cousin Waraqah ibn Nawfal (a Christian) reassured him that it was the same angel who had visited Moses. Over the next 23 years, this same being delivered the revelations now compiled as the Qur’an.
They teach Jesus was not crucified. That He did not die as an atoning sacrifice (Qur’an 4:157–158). And that salvation is not by grace through faith in Christ’s finished work, but by submission (islām) to Allah plus a scale of good deeds.
These are not minor differences, they strike at the very heart of who Jesus is and how sinners are reconciled to God.
Folks, you've got to understand the significance. These things stand in direct opposition to the apostolic witness. The apostles wrote, "the Word became flesh and dwelt among us" (John 1:14). "He became sin who knew no sin" (2 Corinthians 5:21). "Without the shedding of blood there is no forgiveness" (Hebrews 9:22). Jesus truly suffered, died, and rose bodily (Luke 24:39; 1 Corinthians 15:3–4).
Paul’s words are severe because the stakes are eternal. A false gospel cannot save humanity. Our response must be to bring clarity, prayer, compassion for those caught up in these lies, and boldness to proclaim the real Jesus, Son of the living God. Test every spirit, hold fast to the apostolic message, and do not be swayed. Even by the most dazzling angelic visitor. If the message denies the crucified and risen Lord, do not be moved from the hope held out in Christ alone.
So...all that to say this:
There was this monk, St. John of Damascus, a Christian theologian and priest who lived under Umayyad Caliphate rule in Damascus (675–749 AD). And as a monk at Mar Saba near Jerusalem. He had direct exposure to Muslim society, its administration, and its teachings.
And he wrote about these things and classified Islam not as a new religion but as a Christian heresy. This is an interesting point. He describes it as a deviation from true gospel doctrine, and more akin to Arianism (which denied Christ’s full divinity). He calls it the "superstition of the Ishmaelites" (linking Muslims to Ishmael, son of Hagar). And he goes on to make the claim that Muslim ideas are based upon a "people-deceiving cult", and even a "forerunner of the Antichrist."
His main arguments included criticism about the sources. For instance, pre-Islamic Arabs were idolaters, worshiping a stone. Add to these pagan influences the fact that Muhammad encountered the Old and New Testaments and conversed with an Arian (heretical Christian) monk, from whom he derived distorted teachings.
John of Damascus argued that there we no witnesses to Mohammed's revelations. There were no prior biblical prophecies foretelling Muhammad. His revelations came privately, even in sleep, lacking credibility. His writings confuse Mary (the mother of Jesus) with Miriam (the sister of Moses and Aaron), calling her "sister of Aaron" (based on Qur’an 19:28). He denies Christ’s divinity, rejects the trinity, and ridicules biblical visions of paradise. John goes on to criticize Muhammad for fabricating teachings that justify his personal desires (laws on marriage, and divorce). And makes many comparisons contrasting Islamic practices with Jewish/Christian ones. But what I find most interesting is his Christological focus.
John of Damascus argued that Islam is primarily a Christological heresy:
It affirms Jesus as a prophet born of a virgin but denies His crucifixion, divinity, and sonship. Not unlike Doecitism and Arianism. He writes about these things in The Disputation Between a Saracen and a Christian.
It takes the form of a fictional dialogue between a Muslim ("Saracen" ) and a Christian. The intent was to equip Christians with arguments against Islamic objections while defending core Christian doctrines. It unfolds as a series of questions from the Saracen, which are then answered by the Christian:
Saracen: Who causes good and evil?
Christian: God causes only good. Evil arises from human free will, which God permits out of respect for freedom.
This defends God’s goodness while affirming human responsibility. The Christian is arguing that God permits but does not command evil, preserving free will and divine sovereignty.
The Saracen objects to the idea of God having a son or becoming incarnate.
The Christian uses analogies (master-slave relationship) to explain hierarchy without inequality, and also emphasizes baptism’s role. The Christian responds with a clever analogy about John, who he imagines, served as a minister/slave in baptism, not as a superior. In fact John basically makes that case to Jesus, and of course Jesus corrects him regarding his baptism by John. This upholds Christ’s divinity.
Saracen: If you say "He who sanctifies is greater than he who is sanctified," then worship John the Baptist, who baptized Christ!
Christian: You say an owner is greater than what he owns. Yet John the Baptist ministered to Christ as a servant in baptism, breaking the heads of demons in the Jordan. At this the Saracen marveled greatly, and, having nothing to answer, and went away.
John of Damascus is drawing on traditional wisdom. It’s a testament to early theological resilience amid the changing empires. He shows a deep familiarity with Muslim thought.
At the end of the day John of Damascus classifies Islam as the "still-prevailing yet degenerate superstition of the Ishmaelites". And I gotta tell ya, it may seem unkind, but I see it and many of the other variations of Doecitism and Arianism as exactly that, "superstition". Born out of the spirits of paganism (Mohammed influenced by an Arian monk). All these errors are from ancient paganism, mingled with Judaism, and Christian deviations (Arianism, Nestorianism, Monophysitism). And exactly the kinds of things the apostle Paul warned about.
And so all this is interesting, but do not think that witnessing these things and writing about them exempts the priest from finding himself safe from his own forms of superstitions. For instance, John of Damascus argued vigorously for iconography. In fact so much so that his work earned him the title "Doctor of Christian Art." From my very Protestant perspective, John’s iconophilia, while rooted in anti-Docetic Christology, went too far, introducing yet another form of "superstition" akin to what he condemned in others.
Just goes to show that we can be right and wrong in the same lungs that give breath to what comes out of our mouths.
We all have blind spots. John was spot-on in defending the full divinity and humanity of Christ against Gnostic-like denials (whether in Islam or other ancient heresies), tying directly to Paul’s warnings in Galatians. Yet on icons, sincere Christians remain divided. some see it as faithful extension of the Incarnation, others as unnecessary risk of superstition.
This should drive us to humility, Scripture, and grace in our disagreements. The key is clinging to the apostolic gospel. Christ crucified, risen, and fully God-man; no additions, no subtractions.
Heavenly Father,
We stand in awe of Your Son, Jesus Christ, the eternal Word made flesh, crucified for our sins, risen in victory, and reigning forever as Lord and Savior. Guard our hearts against every false gospel and every deceptive spirit. Give us discernment to test every message against the apostolic truth, courage to proclaim the real Jesus, and compassion to share Your grace with those who have heard another voice.
Forgive us where we have clung to superstitions or distortions of our own, and purify us by Your Spirit. May we hold fast to the gospel of grace alone, through faith alone, in Christ alone.
To You, Father, Son, and Holy Spirit, one God, be all glory, now and forever.
Amen.