When discussing religion with a Muslim, one of the common tactics you will encounter is the Red Herring fallacy, wherein a Muslim will attack the Christian’s beliefs in order to demonstrate the validity of Islam. What a Christian believes, or how he practices that belief is irrelevant to the question of whether Islam is the inspired word of God or the insane mumblings of a paranoid schizophrenic with a god complex. Nevertheless, when debating a Muslim, you will be charged to defend your own beliefs and practices. This does two things for the Muslim – It places you on the defensive, thus removing the requirement for them to not answer uncomfortable questions about Islam which they’re not prepared to answer, and it attempts to cast doubt upon your moral authority to cast judgment on Islam.
The moral authority is a logical fallacy – any Muslim should be proud to use such a discussion as an opportunity to instruct the infidel in the ways of Islam and demonstrate why the infidel’s logic is in error. But they do not do this, they shy away from such opportunities the way roaches run from the light. This implies that they are afraid of what the harsh light of reason will do to their cult beliefs.
As far as being on the defensive, no Christian should be afraid of this, and should be well-armed to easily defend the Christian faith and turn to use it to demonstrate the fallacies of Islam. The advantage the Christian has here is that most Muslims have not read the Bible, and anything they know about the Bible is normally from Islamic apologetic websites, taken out of context and presented with editorializations that twist the meaning of the simple truth. Twisting the truth to be something other than what it is, this is Satan’s strength. Witnessing the truth in context is normally all that’s required to reveal such lies.
In a recent debate with a Muslim, A Muslim attempted to turn the discussion away from uncomfortable questions I was asking about Islam with the irrelevant question, “So who gave you right that don`t [sic] follow Old Testament??” The following is my answer.
Christ is the embodiment of the law. The Old Testament Law was written for the nation of Israel to follow in the way of the Lord. It was also very very difficult to keep to that law, which demonstrated the need for Salvation through Christ. In Paul's letter to the Galatians we see (Gal 3:23-29):
Now before faith came we were held in custody under the law, being kept as prisoners until the coming faith would be revealed. Thus the law had become our guardian until Christ, so that we could be declared righteous by faith. But now that faith has come, we are no longer under a guardian. For in Christ Jesus you are all sons of God through faith. For all of you who were baptized into Christ have clothed yourselves with Christ. There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female – for all of you are one in Christ Jesus. And if you belong to Christ, then you are Abraham’s descendants, heirs according to the promise.
Christ's law is simple. The Law given unto Moses was very detailed, given as if to a small child of what one can do and what one cannot do. Christ's law was a law for the thinking man, a law that discards the zero tolerance of the Old Testament and allows men to understand the concept behind the law, so they can apply it without having to know the specifics. (Matthew 22:36-40):
“Teacher, which commandment in the law is the greatest?” Jesus said to him, “‘Love the Lord your God with all your heart, with all your soul, and with all your mind.’ This is the first and greatest commandment. The second is like it: ‘Love your neighbor as yourself.’ All the law and the prophets depend on these two commandments.”
Indeed, on more than one occasion, Jesus reminded us that the law is an ass, that the law was made for man, not man for the law (Mark 2:23-28):
Jesus was going through the grain fields on a Sabbath, and his disciples began to pick some heads of wheat as they made their way. So the Pharisees said to him, “Look, why are they doing what is against the law on the Sabbath?” He said to them, “Have you never read what David did when he was in need and he and his companions were hungry – how he entered the house of God when Abiathar was high priest and ate the sacred bread, which is against the law for any but the priests to eat, and also gave it to his companions?” Then he said to them, “The Sabbath was made for people, not people for the Sabbath. For this reason the Son of Man is lord even of the Sabbath.”
And Mark 7:14-15 (This chapter has a very lengthy condemnation of people who live by the letter of the law and do not observe the spirit of the law, which I won't repeat here because of space. I strongly encourage you to read it for yourself):
Then he called the crowd again and said to them, “Listen to me, everyone, and understand. There is nothing outside of a person that can defile him by going into him. Rather, it is what comes out of a person that defiles him.”
In the early church there was a serious question of whether Gentiles needed to become circumsized to become a Christian. This was answered by the closest followers who knew Christ the best, and showed that the Law of the Old Testament had some common sense injected into it by Christ. There are several examples of this to the Romans, Corinthians, Galatians & Colossians. I quote here from Paul's first letter to the Corinthians, 7:18-19:
Was anyone called after he had been circumcised? He should not try to undo his circumcision. Was anyone called who is uncircumcised? He should not get circumcised. Circumcision is nothing and uncircumcision is nothing. Instead, keeping God’s commandments is what counts.
In Paul's letter to the Romans is a repeat of the answer to this question (Romans 10:4-9):
For Christ is the end of the law, with the result that there is righteousness for everyone who believes. For Moses writes about the righteousness that is by the law: “The one who does these things will live by them.” But the righteousness that is by faith says: “Do not say in your heart, ‘Who will ascend into heaven?’” (that is, to bring Christ down) or “Who will descend into the abyss?” (that is, to bring Christ up from the dead). But what does it say? “The word is near you, in your mouth and in your heart” (that is, the word of faith that we preach), because if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.
Finally, in Ephesians, we see that the law of commandments in decrees was nullified by Christ's sacrifice on the cross: Ephesians 2:13-16.
But now in Christ Jesus you who used to be far away have been brought near by the blood of Christ. For he is our peace, the one who made both groups into one and who destroyed the middle wall of partition, the hostility, when he nullified in his flesh the law of commandments in decrees. He did this to create in himself one new man out of two, thus making peace, and to reconcile them both in one body to God through the cross, by which the hostility has been killed.
Christians are under the spirit of the Old Testament Law in principle, but have been given the grace through the sacrifice of our Lord Jesus Christ on the cross to apply that law humanely, with common sense, in recognition that the law serves Man, not Man the law.