Islam is considered by its followers to be the one eternal religion for all of mankind and that Mohammed was the last and greatest prophet. They include in their list of prophets Adam, Abraham, Moses, David, and Jesus. Mohammed believed that he stood in this line of prophets and that he was in continuity with them. Islam’s great Shahadah or confession claims, “There is no god but Allah, and Mohammad is the prophet of Allah.” Allah, although he is radically transcendent (that is he is completely unapproachable by man and cannot even be described using human language), communicated to Mohamed through the angel Gabriel. What was taught by Gabriel was eventually (twenty years after Mohammed’s death) written down and collected into the 114 surahs (chapters) known as the Koran.
The Koran is the holy book of Islam and has some similarities with the Old Testament. It has some of the same characters and stories. For example the Koran teaches that Allah made the world and everything in it in six days. Adam was created on the sixth day and he and his wife ate of the forbidden fruit. What is interesting at this point however is that Muslims do not believe that God created man in his own image. They also reject the concept of any sin nature in man, instead they believe that they have the ability to believe and obey. Since there is no concept of indwelling sin they believe there is no need for redemption. Instead salvation is simply understood in terms of deliverance from the final judgment; believing in Allah adhering to the basic tenants of Islam will in the end save you as long as your good deeds outweigh your bad deeds.
Anyone with even a basic understanding of the Christian scriptures would see how Islam and Christianity do not comport with one another. Since Christianity is true, and Islam does not comport with it, Islam must be false. We presuppose the Truth of the Biblical world and life view and therefore reject what is contrary to it.
I believe that I can safely say that the Achilles heel of the Islamic worldview is in the area of epistemology (knowledge). How do they know what they know? Muslims source of knowledge comes from the Koran. The Koran acknowledges the Bible and yet contradicts the Bible. This is a glaring inconsistency. Especially considering that the Bible is the earlier of the two and in the Bible it says that God’s revelation to man will not contradict itself and that if anyone comes teaching something in opposition to what God has revealed it should be rejected (Deuteronomy 13:1-5). In fact the false teacher should be put to death. Mohammed then was a false teacher and therefore all the adherents to his teachings are following a false religion. By claiming to accept the Bible the Koran is refuted. Also, the Koran describes Allah who is supposedly indescribable in human language. This makes it impossible for the Koran to be what it claims to be; since it describes a god who cannot be described. The Koran as the source of Knowledge and revelation for the Muslim is inconsistent. If it is inconsistent it cannot be the true word of God; therefore, it must be rejected.
Another, area where we can critique the Koran is more of an ethical dilemma. That is that there is no plan of redemption in their system. In Islam it is understood that man sins and will be held accountable for his sin. In the end they say your good deeds must outweigh you bad. Of course we might wonder if Allah gives more weight to good deeds than to bad and if things left undone which ought to be done are counted against them. However, this is not really the point. Because, Allah is considered holy and unapproachable by man and Allah cannot tolerate sin but punishes it. How can a man be presented before Allah if he has any sin? It is not that the good has to outweigh the bad ultimately but that if there is any bad it must be purged away. However, Islam does not provide for this. There is no way for man to be right before Allah because his iniquities cannot be atoned for. For Muslims then to be saved Allah would have to be unjust and willing to tolerate sin as long as it isn’t too much. This is not consistent with the Koran’s teaching about Allah.
The Bible makes clear that sin cannot be tolerated by a Holy God. The Law of God declares that without the shedding of blood there can be no remission of sins. No mere man, however, is able to pay for sin and good deeds do not erase bad deeds. Praise be to God, that He sent His Only Begotten Son the Lord Jesus Christ who became man to redeem a people unto Himself. Only Christianity provides for the forgiveness of sin, which man has committed, through the shed blood of Jesus Christ. As Christians we know that we have a right standing before God because our sin does not weigh us down. Our good deeds do not need to outweigh our bad deeds, because our sins were nailed to the cross with Jesus when He took them upon Himself and paid the penalty for our sins in our place. Therefore, God is both Just and Justifier. The Muslim has no savior and is therefore lost. This ought to motivate us to work towards the evangelism of the Muslim people. Instead of invading their lands with soldiers we must infiltrate with the Gospel of Jesus Christ, who alone provides peace with man and God.