Here’s an article from one of my mentors from Denver Seminary, Doug Groothuis.  In the article, “Do Christians and Muslims Worship the Same God?”, Groothuis offers a concise answer to this most intriguing question on the suggested unity of belief shared by Christians and Muslims.   
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Muslims and Christians both worship one God, and many would argue that they are the same God.  Are they?

Muslims and Christians: How to Get Along?
They both believe in one personal and transcendent God who has sent his prophets into the world. They both believe in sacred writings that record the prophetic revelations. They both believe that Jesus was a prophet who was sinless and born of a virgin. And they both worship with these beliefs firmly in place. We are speaking of Muslims and Christians, whose members comprise the two largest monotheistic religions in the world.

In the wake of the terrorist attacks of September 11, 2001, Americans have become fascinated with the beliefs and practices of Islam, which is the fastest growing religion in the world, with approximately 1.3 billion adherents. Increasingly, Muslims are immigrating to the West. In various American cities, it is not uncommon to find mosques — many of them newly built — and to see women in the traditional Muslim dress mingling with American women dressed quite differently.

Muslims and Christians comprise the two largest monotheistic religions in the world. 
In light of this, many Westerners wonder what do Muslims believe and why. They also question the relationship between Islam and Christianity. Do Muslims and Christians worship the same God, but merely in different ways? Should Christians seek to present their beliefs to Muslims in the hope that the Muslim might forsake Islam and embrace Christianity? Or is this simply a waste of time at best or rude at worst?

Many instruct us to be “tolerant” and to refrain from “proselytizing” anyone. In the name of tolerance, some people say that Christians and Muslims should coexist without trying to convert (or otherwise challenge) each other because “Christians and Muslims worship the same God.” This, many believe, should be good enough for Muslims and Christians. Many also believe this arrangement is good enough for the God they both worship as well. If both religions worship the same God, why should they worry about each other’s spiritual state?

Religion, God and Truth
If indeed Muslims and Christians worship the same God, there would be little need for disagreement, dialogue, and debate between them. If I am satisfied to shop at one grocery store and you are satisfied to shop at another store, why should I try to convince you to shop at my store or vice versa? Do not both stores provide the food we need, even if each sells different brands? The analogy is tidy, but does it really fit?

Deeper questions need to be raised if we are to settle the question of whether Christians and Muslims worship the same God. First, what are the essential teachings of Christianity and Islam? Second, what does each religion teach about worshipping its God? Third, what does each religion teach about the other religion? That is, do the core teachings of Islam and Christianity assure their adherents that members of the other religion are fine as they are because both religions “worship the same God”?

In When Religion Becomes Evil (Harper. San Francisco, 2002), Charles Kimball argues that Christians and Muslims do indeed worship the same God. Kimball rightly observes that truth claims are foundational for religion. But he claims that believers err when they hold their religious beliefs in a “rigid” or “absolute” manner. So, he argues, when some Christians criticize the Islamic view of God (Allah) as deficient, they reveal their ignorance and bigotry. Kimball asserts that “there is simply no ambiguity here. Jews, Christians, and Muslims are talking about the same deity” (p. 50). This is because the Qur’an affirms that Allah inspired the Hebrew prophets and Jesus. Moreover, the Arabic word “Allah” means “God.” Are Professor Kimball and so many others who echo similar themes correct? In search of a reasonable answer, we will briefly consider the three questions from the last paragraph.

Christianity and Islam: The Claims, the Logic, and the Differences
First, what are the teachings that each religion takes to be absolutely true? Although Islam and Christianity are both monotheistic, their views of God differ considerably. Islam denies that God is a Trinity — that one God eternally exists as three co-eternal and equal persons: the Father, the Son, and the Holy Spirit (Matthew 28:19).1 Islam also rejects that God became a man in Jesus Christ (John 1:1-18).2 These doctrines are cornerstones of Christianity. But God cannot be both a Trinity (Christian) and not a Trinity (Islam). This is matter of simple logic; it has nothing to do with religious intolerance or being “rigid.”

Although Islam and Christianity are both monotheistic, their views of God differ considerably.
For Christianity, humans are corrupted by an inherited sinful nature that cannot be overcome by any human means (Ephesians 2:1-10). But Islam denies that humans have a deeply sinful human nature, claiming that we sin because we are merely weak and ignorant.3 Christianity teaches that salvation is secured only through faith in the achievements of Jesus Christ — his life, death, and resurrection (John 3:16-18). Islam, however, implores its followers to obey the laws of the Qur’an in the hopes that they will be found worthy of paradise.4 Since these two views contradict each other, both views cannot be true.

Second, how does each religion say worship should be offered to God? Muslims deem worship of the Trinity to be polytheistic and thus blasphemous. Worship of Jesus — whom they deem only human — is anathema. Yet these beliefs are essential for Christian worship. One must worship God “in spirit and in truth” (John 4:24). Worship requires assent to the truth of God (the Trinity), belief in the gospel, trust in Jesus Christ, and submission to God’s will. While Muslims emphasize submission to Allah (“Islam” means submission), they do not submit to the God revealed in the Bible. This exposes another irreconcilable difference between Islam and Christianity.

Third, what does each religion make of the other one? Muslims and Christians have historically tried to convert each other, since they both view adherents of other religions to be misguided. Islam seeks converts worldwide because it believes Allah is supreme over all and must be so recognized. Christians are commanded to take the gospel into all the nations and to baptize converts into the name of the triune God of the Bible (Matthew 28:18-20). Neither Christianity nor Islam can logically endorse the other religion’s distinctive claims and practices without denying its own.

Much more needs to be discussed concerning Muslim and Christian relations in a religiously pluralistic world. However, we must conclude that despite their common monotheism, Islam and Christianity have very different views of God, worship, and mission. Therefore, it is unreasonable to claim that they worship the same God.

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Notes
1. See The Qur’an, Surah 112:1-4, which denies that God “begat” a son. Surah 4:171 commands Muslims to not say “three” with respect to God; see also Surah 5:73. However, the Qur’an claims that the Christian doctrine of Trinity affirms that it is comprised of the Father, the Son, and Mary (Surah 5:116). The Bible, however, never attributes deity to Mary. For more on how the Qur’an understands Jesus and the Trinity, see Chawkat Moucarry, The Prophet and the Messiah: An Arab Christian’s Perspective on Islam and Christianity (Downers Grove, IL: InterVarsity Press, 2001), 184-195.
2. See The Qur’an, Surah 5:115-18 where Jesus is reported to have denied his own deity; see also Surah 9:30-31.
3. See Harold Netland, Dissonant Voices: Religious Pluralism and the Question of Truth (Vancouver, BC: Regent University Press, 1997), 89-90.
4. See the Qur’an, Surah 36:54; see also Surah 82:19.

About the author

Douglas Groothuis, Ph.D., is Professor of Philosophy at Denver Seminary where he directs the Philosophy of Religion Masters Degree program. He has authored ten books, including Unmasking the New Age, Truth Decay, On Jesus, and On Pascal, as well as many publications in academic journals and magazines.
Copyright © 2005 Douglas Groothuis. All rights reserved. International copyright secured.