If Islam is a Christian heresy you would find much in Islam that agrees with Christianity especially in major things. Although there is much that Islam and Christianity agrees with, which is true of all religions, some of the major defining pillars of Christianity, Islam is definitely against. Let me list a few:
- Christianity teaches the 3 in 1 G-d concept of the trinity. Islam teaches that G-d is one and that it is a great sin to claim that He is one in a trinity.
- Christianity teaches that Jesus is the son of G-d and divine. Islam teaches that Jesus was no more than a righteous Prophet and only a human being.
- Christianity teaches that man is born in sin. Islam teaches that G-d created the human being in the most excellent mode. Physically, mentally and spiritually. The human being only learns sin from his/her experience in this world. According to Islam he is not born that way.
- Christianity teaches that Jesus is the Savior of mankind and died for our sins. Islam teaches that no one is our savior. We have free will to decide on our actions. As a result we EARN salvation by what we do of good and we EARN damnation by what we do of evil. There is no vicarious atonement in Islam.
- In Christianity, as exhibited by the Inquisition, only those belonging to the Christian faith and accepting Jesus as their Lord and Savior, will go to heaven. All others are infidels going to hell. In Islam it clearly states in numerous places that ANY person who believes in G-d and works righteous deeds regardless of religion will go to heaven.
- Christians believe the crucifixion of Jesus to be a fact. Muslims believe that Jesus was never crucified.
- The Bible teaches that it was Eve, a woman, who caused the fall of Adam and thereby the fall of mankind. In Islam Eve does not exist. The blame for Adam’s fall is put on him following the wiles of Satan. His fall was his own and NOT all of humanity’s.
- In Christianity some the Prophets of G-d are depicted as committing all manner of evil deeds. Moses is depicted as a blood thirsty conqueror killing innocent men, women and children on behalf of the children of Israel. David sends his best general to be killed so that he could have sex with his general’s wife Bathsheba. Lot is depicted as getting drunk and sleeping with his daughters. And there are many more examples throughout the Bible. Islam teaches that those grave charges against G-d’s Prophets are false. None of the Prophets of G-d committed those sins.
- In Islam the right to own property, vote and initiate divorce was given to women 1400 years ago by the revelation of the Quran and the example of the Prophet (saaw). In Christianity no such rights exist in their religious text and women recently won those rights in the 1920s.
- In Christianity scientific pursuit was discouraged. Scientists and scientific thinking that differed from Christian doctrine were condemned and some Scientists were even killed for daring to expose their scientific findings that differed from Christian doctrine. In Islam scientific pursuit was encouraged. The Quran in numerous places challenges and exhorts the “akiloons”, those who use their minds, to pursue knowledge and gain understanding of G-d’s vast and beautiful creation. Throughout the history of Islam the most scientific and knowledgeable Muslims were the ones who were the most devout.
I could go on with a lot more. But I hope you can see that with what I have listed and more that I haven’t, that Islam in no way is a Christian heresy.