But there are very real limits for a biblical Christian as to how far one can go with interfaith dialogue, especially when it comes to theology and beliefs. Learning about other religions is one thing, but diluting one's own Christian beliefs merely in order to just get along is another thing altogether.
Take Islam and Christianity for example. While there is some common ground between the two religions, there are major differences as well. Indeed, the very core of Islamic theology is fundamentally opposed to the very core of Christian theology. To affirm one is to renounce the other. Both cannot be held to simultaneously, without repudiating logic in general, and the law of non-contradiction in particular, let alone repudiating each belief system.
Take the issue of the deity of Christ, his eternal existence, and his oneness with the Father. All of this is bedrock Christian teaching, but all of this is denied in Islam. Muslims revere Jesus and look to him as one of a number of important prophets, but they utterly reject his claim to divinity, or being the son of God (eg., Surah 19:35). The Koran teaches that Jesus was simply a messenger, like those who had passed away before him (Surah 5:75).
But the New Testament makes it plain that if someone denies these basic truths, then they have nothing to do with God or the truth. They are in fact false prophets and deceivers. A number of passages spell this out very clearly:
"Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world" (1 John 4:1-3).
"Many deceivers, who do not acknowledge Jesus Christ as coming in the flesh, have gone out into the world. Any such person is the deceiver and the antichrist" (2 John 7).
These – and other passages – tell us much about the eternal deity of Jesus Christ. When they tell us that he has come in the flesh they of course speak to his pre-existence, and the fact that Jesus is the Son of God.
Islam regards it as blasphemous to think that God could have a son. So the very heart of Christianity, the notion that God has become incarnate in the person of Jesus Christ, is denied by Muslims. They regard it as the height of blasphemy. And biblical Christianity, as these passages assert, regards those who deny the incarnate Son as being deceivers and in fact of the anti-Christ.
Indeed, to reject the Son (as he presents himself) is to reject the Father. Jesus made this perfectly clear in his teachings. Consider a few of many passages in which Jesus speaks to this truth:
-John 5:22-23: Moreover, the Father judges no one, but has entrusted all judgment to the Son, that all may honor the Son just as they honor the Father. He who does not honor the Son does not honor the Father, who sent him.
-John 8:19: Then they asked him, "Where is your father?" "You do not know me or my Father," Jesus replied. "If you knew me, you would know my Father also."
-John 12:26: Whoever serves me must follow me; and where I am, my servant also will be. My Father will honor the one who serves me.
-John 12:44-45: Then Jesus cried out, "When a man believes in me, he does not believe in me only, but in the one who sent me. When he looks at me, he sees the one who sent me.
-John 15:23: He who hates me hates my Father as well.
Sure, Muslims honour Jesus as a prophet, but they reject his claims to be God's son and the only saviour. Plenty of people honour Jesus – even pagans do that. But to properly honour Christ is to receive him and his claims, and not just accept some whitewashed version of him.
But it gets even more impossible to reconcile the two faiths. Perhaps the height of Christian belief and teaching is that Jesus Christ died on a cross for our sins, and then rose again on the third day. This is the utterly basic and bedrock teaching which distinguishes Christianity from all other religions. It is such a central and core belief, that the apostle Paul could even say that if Jesus did not rise from the dead, then our faith is in vain. Indeed, if there is no resurrection, then we are still dead in our sins, and we are of all men to be most pitied, he says (1 Cor. 15:12-19).
Islam of course flatly denies that Jesus died on a cross and rose again (Surah 4: 157-158). So again, we have two completely contradictory views on the crucial doctrines of Christianity. If what Islam teaches about Jesus is true, then the biblical teachings cannot be true. But if what the New Testament says about Christ is true, then Islam cannot be true - at the most fundamental level. It is as simple as that.
So how exactly are Christians to get along with Muslims, theologically speaking, when they deny the very heart and soul of the Christian Gospel? Certainly we can get long as friends, as neighbours, as workmates, and so on. We can even get along as co-belligerents, working together on common causes. I have myself worked together with Muslims on various pro-family initiatives.
But just how are the two religions to co-exist on a theological level, when they affirm mutually contradictory propositions about God and his son? A biblical Christian shares very little major theological common ground with a Muslim, and vice versa. Thus any attempts by interfaith dialogue groups to try to water down these differences, or to seek to patch over these significant doctrinal differences, are doomed to failure.
Again, Muslims and Christians can come together and discuss these issues. But a real Muslim will not want a watered down version of Islam. A real Muslim will want to see everyone become a Muslim like himself. Likewise, a real Christian will want everyone to be introduced to a personal, life-changing relationship with Jesus Christ.
Too often however these interfaith meetings are all one-way traffic. Too many Christians are willing to sacrifice key Christian beliefs in the interests of getting along, of being loving and appearing tolerant. And too many Muslims are quite happy to exploit such endeavours for their own ends.
Jesus told us to be wise as serpents and harmless as doves. We are also told to test the spirits. Those Christians going into interfaith dialogue need to be very careful indeed. They need to properly know what they believe and why. And they need to be aware that there is a satanic and deceptive presence in the world which is seeking to lead people astray.
Paul tells us not to be ignorant of Satan's devices. We must test all things, and not allow ourselves to be deceived by various false prophets and various well-meaning interfaith advocates. Too many gullible Westerners have already fallen for some classic misinformation about Islam. And too many Christians are suffering in dhimmitude in Muslim nations around the world. Indeed, the suffering and persecution they face is immense, and many are dying for their faith in these lands. For their sake, we dare not allow ourselves to be duped by apologists of Islam, or any other non-Christian worldview or religion.