Those who argue that Islam and Christianity are quite similar really know very little about either religion. While there are some common features, the differences are many and substantial. To believe in one means you cannot believe in the other. Each one rules out the other. Here then are some of the major differences.
Revelation and the Bible
Islam The Koran is the Word of God and the central focus of revelation. It was revealed to Muhammad by the angel Gabriel, although Muhammad was merely the recipient through whom the word passed. Although God spoke through many prophets (such as Moses, David, Christ and even men like Alexander the Great), the Koran annuls all of these previous revelations. The Koran is the final, perfect, and universal message of God. Conflicts between the Bible and the Koran are due to Jewish and Christian alterations and corruptions of the Biblical text.
Christianity The Bible is the Word of God and Jesus Christ is the central focus of revelation. God has revealed Himself both in the written word, the Bible, and in the human word, Jesus Christ. Christ didn’t just bring a revelation from God, but is Himself the revelation of God. All Scripture (both Old and New Testament) is inspired by God, and is authoritative in all it affirms. The New Testament canon was closed with the book of Revelation, and further claims of inspired writings are to be rejected.
Islam Allah is totally transcendent and inaccessible to man. We have no personal self revelation of His character and all we know of Him is through what He has commanded. The foundation of Islam is the oneness and omnipotence of Allah. The love of God is rarely stressed. He is a despotic sovereign, not a loving Father. He is the God of fate who has unalterably predestined all things, evil as well as good. He is bound to no moral absolutes and His actions are determined simply by His own arbitrary will.
Christianity While God is transcendent, He is also personally concerned with, and intimately involved in, the affairs of men. His omnipotence is tempered by His moral character. His mercy never conflicts with His justice, righteousness and holiness, as there is a unity in His moral character. God is a heavenly Father who loves all men equally and desires to have fellowship and communion with them. However, His holiness demands that we approach Him cleansed of our sin, which the work of Christ makes possible. The love of God is an essential part of His nature – indeed, God is love. His actions are only always righteous and just.
Islam Isa, or Jesus, is revered as a Prophet but His divinity is vigorously denied. He was a mere man, only a messenger of Allah created by God. He was born of the virgin Mary, performed miracles, and yet disclaimed divine honours. Since it was unjust for the innocent and sinless Christ to die a criminal’s death, an “appearance” or a substitute was crucified on the cross, while Christ ascended to heaven where He now occupies an inferior station. One day He will return as one of Muhammad’s caliphs to help establish Islam as the world’s one true religion. On the side of the Dome of the Rock in Jerusalem it says in Arabic, “God has no son”. Contrast this with Matthew 3:17: “This is my Son, whom I love”.
Christianity Jesus Christ is the second person of the Trinity, God’s final and perfect word to man. He came not just as God’s messenger, but as God incarnate, as Saviour and Lord. He is eternal and without sin, (and, since the incarnation) fully God and fully man, two complete natures in one person. He died on the cross for man’s sin and rose again on the third day, ascending to heaven. As predicted in the Old Testament, He will one day come again as Israel’s Messiah to set up His kingdom on earth and to subdue His enemies. Jesus Christ is the culminating thought of the Old Testament and the chief subject of the New Testament. He is the King of kings and the Lord of lords to whom every knee will one day bow.
The Holy Spirit
Islam The term “Spirit of God” can mean breath, a created being, such as Gabriel, or even Jesus, but it does not refer to God Himself. Muhammad is viewed by some Muslims as the comforter, or counselor, which Christ promised in John 14:16.
Christianity The Holy Spirit is the third person of the Trinity. He is eternal, omnipotent, and omnipresent, as are the other two members of the Trinity. The Holy Spirit is fully God and is also fully personal. The comforter which Christ predicted would come was not a man but a Spirit, who came to testify of Christ and indwell His disciples. It is through the Holy Spirit that the power and love of God is made manifest in the believer’s life.
Islam Allah is one. To worship anyone else but Allah is idolatrous and unforgivable. Christians worship God, Mary and Jesus. (Islam erroneously understands Christianity to mean by the doctrine of the Trinity three gods: God the Father, Mary the Mother, and Jesus the Son.) The term “Son of God” is also blasphemous, for God did not take a wife and physically beget a child.
Christianity In the Bible the One God has revealed Himself in three ways: as Father, as Son, and as Holy Spirit. In the Bible all divine titles and attributes are ascribed equally to the Father, the Son, and Spirit. Christians are equally opposed to the idea that there are three gods, or that God physically had a son. The term “Son of God” is to be understood in a spiritual, not a physical, sense. Jesus is the eternal Son of God. The Athanasian Creed explains the Trinity in this way: “We worship One God in Trinity, and Trinity in Unity; neither confounding the Persons, nor dividing the Substance.”
Islam Compared to the greatness of God, man is insignificant. His relation to Allah is that of a slave to his master. All that man can do is obey Allah as a bondslave and submit to His will (the word “Islam” means submission). Since Allah alone can create, man has no ability to create his own acts; he therefore has no free will. All of men’s actions are the creation of Allah.
Christianity God made man in His image to live in loving, personal fellowship with Himself. He created man with a free will so that man might voluntarily respond to His love. He intended that we be His children, not His slaves. The work of Christ on our behalf shows us how important we are to God and how much he loves us.
Islam The practical outcome of the Islamic view of man is the denial of all human responsibility. Since sin, like all else, is as Allah wills, Muslims have little or no sense of their own sinfulness. The Fall is seen as a physical, not a spiritual, fall (i.e. man fell out of Paradise to the earth below). Original sin is denied, although man is said to be born weak. Muslims, therefore, do not seek salvation, but guidance and direction in their spiritual journey.
Christianity Man, with his free will, chose to reject God and His love, and now lives in alienation from Him. This choice to live without God is the essence of sin. It is proud independence and selfishness. All men after the Fall have chosen to reject God, and all men have sinned. Man is the author of sin, not God. It was never His will that men should sin. Sin is an abhorrence to God and is the source of the problems and misery in the world today. Sin is not just words and actions, but is rooted in our very nature.
Islam Islam has no Saviour. Confession of the Creed (“There is no God but Allah…”) brings one into the Islamic community, wherein one seeks to earn his salvation by performing the religious duties and doing good works. At the Judgement Day men’s good deeds and bad deeds will be weighed, although ultimately, forgiveness is based on the arbitrary will of Allah. Allah saves those whom He chooses to save, and damns those whom He chooses to damn, with little or no moral basis for such choices.
Christianity It is God’s desire that all men be delivered from the power and penalty of sin, and be restored to a right relationship with Himself. Man by his own efforts is unable to please God or undo the effects of sin. Therefore God became man and lived a sinless life, and through His death on the cross fulfilled the demands of the law upon sinners, taking their penalty for sin upon Himself. Thus by His death He conquered sin, and by His resurrection He conquered death. God is now, on the basis of Christ’s substitutionary atonement, able to receive us unto Himself, when we turn from our sin and commit our lives to the Lord Jesus. By grace we are saved through faith. Good works do not procure our salvation but follow as an evidence of it.
Clearly then, on all the key doctrinal issues of the faith, Islam and Christianity are poles apart. To affirm the main teachings of Islam means to renounce those of Christianity, and to affirm biblical Christianity means of necessity to reject the basic tenets of Islam. The two are not at all similar, and can never be.
For more on the differences, especially in terms of political, social and culture values, see here: www.billmuehlenberg.com/2013/03/19/islam-and-christianity-c