According to Pew Research, if current trends continue then by 2050 there will be nine billion people living on the planet. Approximately three billion will be Christians, three billion will be Muslims, and three billion others will represent various beliefs (both religious and secular).1
Since Christianity and Islam are the two largest (comprising about 55% of the world’s population2) religions in the world people often wonder where they disagree and how significant the differences are. A brief look at six doctrinal contrasts will help address this question.
First, it is important to note that Islam shares common ground with historic Christianity. For example, both religions are:
- theistic in philosophical orientation
- monotheistic in doctrinal belief
- Middle Eastern in origin
- biblically oriented Abrahamic faiths (they connect to the Hebrew Bible or Old Testament)
However, the differences between the two religions are profound. Since Islam emerged about six centuries after Christianity, we’ll outline how Islam reacts to essential Christian truth claims. As you’ll see, traditional Islam denies the essence of historic Christianity.
Six Systematic Doctrinal Denials
- Islam denies the Trinity (i.e., tri-unity: One God in three persons). Muslims instead affirm a form of unitarianism where Allah is a single, solitary being (tawhid) with no partners, equals, rivals, or companions. Allah is not begotten nor does he beget; therefore, he has no son.
- Islam denies the incarnation (i.e., Jesus Christ was God in human flesh: a single person with both a divine and human nature). In contrast, Muslims assert that Jesus was a mere human being. Yet Islam does concur that Jesus was virgin-born, performed miracles, and lived a sinless life.
- Islam denies the crucifixion (i.e., Jesus’s atoning death on the cross). Muslims instead declare that Jesus either didn’t actually die on the cross (though he may have been impaled) or that someone else took Jesus’s place on the cross. But either way, Islam is not a redemptive religion.
- Islam denies the imago Dei (i.e., human beings bear God’s image). In contrast, Muslims affirm that such an image would put creatures too close to Allah (the heresy known as “shirk”). Thus in Islamic theology, human beings are not made in Allah’s image.
- Islam denies original sin (i.e., that human beings are born with a sinful nature and a natural propensity to sin). Instead, Muslims assert that people are born morally good. So Islam rejects the Christian doctrine of the fall.
- Islam denies salvation by grace (i.e., that human beings are reconciled to God by God’s unmerited favor apart from works). In contrast, Muslims proclaim that personal submission is required to earn paradise. So both paradise (reward) and divine wrath (punishment) are earned.
Both Can’t Be True
While we live in a time that prizes religious pluralism, nevertheless the laws of logic are stubborn things. Given these six systematic doctrinal denials it follows logically that if Islam is true, then Christianity is patently false and vice versa, for Islam denies the very essence of Christian doctrinal truth claims.
Reflections: Your Turn
Why do you think Islam and Christianity are such popular religions?
Resources
- For a further comparison of Islam and Christianity, see my two books God among Sages: Why Jesus Is Not Just Another Religious Leader (Grand Rapids, MI: Baker, 2017), 159–88; and A World of Difference: Putting Christian Truth-Claims to the Worldview (Grand Rapids, MI: Baker, 2007), chapter 15, 247–63.
- For an introduction to Islam by a Muslim scholar, see Islam: Religion, History, and Civilization by Seyyed Hossein Nasr (San Francisco: HarperSanFrancisco, 2003).
Endnotes
- Pew Research Center, “The Future of World Religions: Population Growth Projections, 2010-2050, April 2, 2015,” https://www.pewforum.org/2015/04/02/religious-projections-2010-2050/.
- Wikipedia, s.v., “List of Religious Populations,” updated May 28, 2020, https://en.wikipedia.org/wiki/List_of_religious_populations.
Reflections 
1. Man desires a relationship with the God-Creator of the universe.
2. Man inherently recognizes his separation from God and seeks redemption.
3. In a “religion,” the different cultures find community within their shared theistic practices.
4. Both religions recognize an unpaid debt for our sin and offer pathways to forgiveness: submission places our choices above those of God; grace places God’s choice over ours.
5. You gotta serve somebody, as a counter-culture poet once said.
Thanks, Ben.
I’m assuming this is your answer to my question at the end of my article:
“Why do you think Islam and Christianity are such popular religions?”
Best regards.
Ken Samples
This analysis is correct.
A followup would explain how the Christian side has developed into western European civilisation; and how the Islamic side has developed into fitful alternations between despotism and stagnant legalism. I can recommend Tom Holland’s “Dominion” for the former.
Islam started as a rallying-point for all the late-antique Christian heresies: Donatism and leftover Arianism along the old Vandal North Africa, Monotheletism in Egypt and Syria, the pre-Nestorian undercurrents in Iraq like Aphrahat (Nestorius himself was more orthodox than many allow). It follows that Protestantism has no future in this world. I expect Protestants will continue their drift to liberalism and thence to Islam.
Zimriel:
Thanks for your comments.
I have Tom Holland’s book Dominion. I need to start reading it.
Your connections between Christian heresies and Islam is interesting.
Protestantism as a branch of Christendom has its challenges. But the common ground on doctrine, values, and worldview shared by the three branches of Christendom (Catholic, Orthodox, Protestant) is robust.
Truth, Unity, and Charity.
Ken Samples
It might be worthwhile to compare Christianity in 1440 AD to Islam in 1440 AH (today) i.e. both religions at the same age since there founding. Christianity was in bad shape, with extreme corruption which led eventually to the Protestant Reformation and almost 2 centuries of slaughter between Christians (Catholic / Protestant) until finally they realized that political leaders should not and cannot dictate the religion of their countries and that everyone had to be free to decide for themselves. Once a system was established in which the success of a religion depended on how GOOD the leadership and the community were, rather than depending on how POWERFUL they were, then the denominations started to compete toward maximum goodness.
A case can be made that Islam is going thru a similar process as Christianity went thru in the 1500s & 1600s. Christianity may be more “advanced” simply because it is a few centuries older and has, during that time, learned what NOT to do.
Jay:
Greetings again.
Four brief points for your consideration:
(1) My article above obviously doesn’t focus on the history of Christianity or Islam but rather on where they agree and disagree in terms of theology. In that context I think what I have written is accurate.
(2) While there have been evil things done in the name of Christ (thus a dark side of Christendom so to speak), some contemporary historians would challenge your claim that there was “almost 2 centuries of slaughter between Christians (Catholic / Protestant).” Much of the hostilities between so-called Catholic and Protestant forces were much more political than religious in nature (thus Europe’s wars more than Christendom’s wars). Chapter 7 of my book below addresses the topic of “Killing in the Name of God” (including the Crusades, the Inquisition, and the Thirty Years War).
(3) While I have no wish to misrepresent or taint Islam’s history, I think a fair comparison of the histories of Christianity and Islam reveals that Islam has had a much greater propensity for violence (again see my discussion of the Crusades in my book below).
(4) Given that Christians and Muslims make up about 55% of the world’s population, it is imperative that both religions learn to respect one another and work toward a viable toleration of each other.
Peace be with you.
Ken Samples
Some useful points, but the overall approach could be used to distinguish Judaism from Christianity. Nothing wrong with being a fundamentalist, but if you want to write for a readership beyond your own faith, you should focus on the distinctions that are truly civilizational; the Muslim belief that we are not made in the image of God, that we are not sinful by nature, and that God’s grace does not operate in human souls.
Isaiah:
Thanks for your comments.
On some points traditional Judaism is closer to Islam than to historic Christianity (generally speaking a religion that emphasizes practice over belief). But Orthodox Judaism does affirm the imago Dei and the basic sinful nature of humanity whereas Islam does not.
What you call “fundamentalism,” I call the orthodoxy of historic Christendom (Catholic, Orthodox, Protestant).
I’ve written more extensively about Islam in my book A World of Difference. But the “civilizational” ideas you note are deeply connected to points of God’s nature and personhood (Trinity, Incarnation, atonement, etc.). Moreover, the three so-called “civilizational” issues you mentioned are noted in my article.
Best regards.
Ken Samples
Consider adding to your list that the Christian God is personal. That is, we can have a personal relationship with Him. That is a Biblical truth, both Old and New Testament.. It is my understanding that the God of Islam is impersonal. That the primary relationship is one of obedience. You can love Allah, but Allah does not love you. Where a Christian has the indwelling of the Holy Spirit and is in Christ. We are in a family relationship as loved adopted children with the Christian God.
Roger:
Thanks for your comments.
In my book A World of Difference I do discuss the deep difficulty of Allah being so transcendent that he seems less than personal or knowable by Muslims. I also discuss Islam not being a redemptive religion.
Best regards.
Ken Samples
And praise God (Jesus) that He is a personal God!
Thanks, Jason.
Ken Samples
As a specification of the Triniity, I would add that while Fatherhood is essential to the Christian deity’s identity, it is completely absent from Islam. Allah is never addressed as a father, certainly not in relation to a divine son but also not to Muslims, who are not his children in any sense, but his slaves. Ascribing fatherhood to Allah smells of shirk.
Polemeros:
Thanks for your comments.
I know the word Father does not appear in the Qur’an. You make an important point that Allah is not a Father not just in terms of divine Sonship but also in terms of human devotion (no adoption).
Thanks.
Ken Samples
Thank you for this article. I think you focused right on point. They are fundamentally opposite and ultimately cannot be reconciled in any way. Islam denies the cross and the Trinity, which are the heart and center of Christianity.
When Jesus described the death he would suffer, Peter said, Oh no, Lord, we won’t let that happen. Jesus replied, Get behind me Satan. But Islam says, Allah would never allow a prophet to suffer a death like his….
Or consider this: When Jesus’s death was approaching, he said that the hour was coming when the ruler of the world (Satan) would be defeated. Allah says, Jesus never died. Hmmmmm….put that 2 and 2 together.
The poverty of Islam is heartbreaking and I pray that Muslims get to know Jesus Christ and find someone incomparably better than they believed in before.
Thanks for your comments, Hety.
Ken Samples
As a Christian, I would be interested to see some subsequent commentary from an Islamic scholar on the points you raise. Have you received any as yet?
Herrmann:
Greetings.
Yes, I’ve had two informal debates with Muslim apologists on the Web and dialogued with Muslim scholars in an academic setting.
I’ve taught college courses in world religions for thirty years and presently teach comparative religions at Biola University.
For a further comparison of Islam and Christianity, see my two books God among Sages: Why Jesus Is Not Just Another Religious Leader (Grand Rapids, MI: Baker, 2017), 159–88; and A World of Difference: Putting Christian Truth-Claims to the Worldview (Grand Rapids, MI: Baker, 2007), chapter 15, 247–63.
For an introduction to Islam by a Muslim scholar, see Islam: Religion, History, and Civilization by Seyyed Hossein Nasr (San Francisco: HarperSanFrancisco, 2003).
Ken Samples
I am glad you put a fair comparison irrespective of your own evaluation. It’s rather shocking to see someone explaining such differences respectfully in todays world.
Thanks, Manahil.
Peace.
Ken Samples
I really liked this. I’m just starting ti become trained in apologetics, and one of the things are studying other religions. This helped a lot and is very insightful!
Thanks, Ashley.
All the best in your study of apologetics.
Ken Samples
To be honest all religions are same. They all speak of the same Lord. Just like we call Father, Dad, Daddy, Bapu, different names but same person, so is religion!
Rejoy:
Greetings.
I’ve taught courses in the world’s religions for thirty years.
All the religions are not the same. Consider one example (and I could give you many others):
Islam affirms one God.
Popular Hinduism affirms 330 million Gods.
Philosophical Hinduism affirms all as God.
Original Buddhism affirms no God.
The world’s religions can’t agree on if there is a God or how manny there are.
Ken Samples
PS See this article: https://reflectionsbyken.wordpress.com/2012/11/27/profound-problems-with-religious-pluralism/
As for Hinduism, I can assure you, Hindus are monotheistic. I am a Hindu myself, and it’s not my own set of belief. Baba Lokenath, Sai Baba, Kabir, Raja Ram Mohan Roy, Ramkrishna Paramhansa, Swami Vivekananda, all of them have spoke of the oneness of God.
But You are an expert, so won’t argue with you. But as a Hindu myself, I know we Hindus have deviated a lot from the scriptures, a lot, and that too in a Good Way.
Rejoy:
Greetings again.
I agree that most Hindus affirm Bhakti (monotheism or monolatrism). I should have mentioned that in my earlier note. However, temple Hinduism affirms polytheism and philosophical Hinduism affirms pantheism.
It seems to me that Hinduism reflects multiple views. Though Bhakti is the dominant view.
Thank you for reading my article and interacting with me.
Best regards.
Ken Samples
tks for posting such an insightful article. i always wondered the main difference between 2 biggest religion.
Thank you Muslims Monitor.
Ken Samples
Revelation is the divine truths that God has given to humankind.
Religion is the record of how we have understood, or mostly misunderstood, those Revelations.
Holding tightly to any human interpretation is an almost sure-fire way to remain lost. If you are uncertain of this, ask the Pharisees of Jesus’ day.
Those who understand the inner essence of the Qur’an and the Bible recognize them as one–all coming from one divine Source, just as Christians recognize the New Testament and the Old Testament as coming from one divine Source.
Jay:
Greetings
Thanks for your comments.
Here’s my response for your consideration:
1. Though I generally accept your basic distinction between revelation (divine given) and religion (human received), there’s no reason to conclude that human beings can’t have a truthful understanding of the revelation even if it is limited in understanding. Orthodox Judaism, historic Christianity, and traditional Islam all believe they have been given doctrinal truth about God. However, some of those doctoral truths logically contradict one another so they can’t all be correct.
2. Jesus Christ never condemned the Jewish religious leaders for affirming the doctrinal truth of the Shema (Deut. 6:4) nor of the imago Dei (Gen. 1:26-28). In fact, Jesus insisted that people needed to hold tightly to those truths.
3. “Those who understand the inner essence of the Qur’an and the Bible recognize them as one–all coming from one divine Source” logically contradict the views of Orthodox Judaism, historic Christianity, and traditional Islam. These so-called insightful ones are actually saying that Orthodox Judaism, historic Christianity, and traditional Islam are all wrong. But who are they to say they alone understand the revelation (kind of sounds like the Pharisees you referenced).
4. Where’s the divine revelation that says Jews, Christians, and Muslims have all misinterpreted the revelation given to their respective communities and that the Tanakh, the New Testament, and Qur’an actually all agree? But since there is a difference between revelation and religion how do they know they are actually correct and the exclusive beliefs of the traditional religions of Judaism, Christianity, and Islam are wrong?
5. Orthodox Jews don’t think the New Testament is on par with the Torah. Traditional Muslims don’t think the Old and New Testaments are on par with the Qur’an. Historic Christians don’t think the Qur’an is on par with the Bible.
Saying that the revelations of the three Middle Eastern monotheistic religions (as are reasonably interpreted by their religious communities) are not in conflict on some important truths is simply uninformed and incorrect.
Best regards.
Ken Samples
Here’s my book that compares Jesus with Krishna, Buddha, Confucius, and Muhammad:
You state that both Islam and Christianity can’t both be true. There is another possibility that you haven’t considered in your article; Neither one of them is true. I base this possibility on the arguments laid out in the following books: Why I Am Not a Muslim by Ibn Warraq; Why I Am Not a Christian by Bertrand Russell; and On the Historicity of Jesus by Richard Carrier. Peace.
Earl:
Greetings.
Yes, I agree.
Since the two religions contradict one another concerning essential truths, they cannot both be true. Logically speaking one could be true and the other false or both could be false.
My article focuses exclusively on the relationship between these two theistic religions in terms of truth claims.
As a philosopher and theologian I am familiar with the sources you reference.
But if either Christianity or Islam is true, then the atheist view is false because the two also contradict.
Some religions are compatible with atheism. For example, Theravada Buddhism. But theistic religions and atheism are contradictory.
Let me recommend one of my books that makes a case for the existence of the God of theism and the truth of Christianity.
Peace be with you also.
Ken Samples