To non-Christians one of the most offensive claims of Christianity is that it provides the only path to heaven. If you are a non-Christian it is certainly understandable why this would offend or upset you, but I would hope you can at least appreciate and respect why it is important for Christians not to skirt such an important tenet of Christianity.
If the Bible truly is the Word of God, wouldn't you agree that it would be incredibly selfish of Christians to fail to mention such a far-reaching, eternally important component of the Bible?
Comparing World Religions
The first thing we should do is determine how the major religions of the world differ from each other, and to ascertain whether these differences are bridgeable. Christianity is based on the Triune God of the Bible - the Father, Son, and Holy Spirit, and particularly the life of the Son, Jesus Christ.
All other religions are based on the writings of men and not the life of any particular individual. Judaism, the sister religion to Christianity, is based on the Old Testament of the Bible, rejecting the entire New Testament and holding that the Messiah has not yet come.
Islam is based on the writings of Muhammad, where they worship a single, impersonal god.
Mormonism is based on the writings of Joseph Smith, where they deny the eternal divinity of Jesus, believe in many gods, and believe men can attain godhood (as their Jesus and Father did) and rule over their own planet.
The Eastern religions, including Hinduism and Buddhism, and Western new-age religions such as Christian Science essentially believe everything is god (Pantheism - may the force be with you). These religions also teach reincarnation until the spirit reaches a level of "enlightenment" and oneness with god or the gods. Christianity teaches one death and one judgment (Hebrews 9:27).
Christianity is also the only religion that recognizes the hopeless gap between man and a Holy and Righteous God, teaching that salvation can only be obtained through God's grace. All other religions teach that salvation can be achieved through human effort.
I think at this point we should be able to agree that that the major world religions are quite different, with many conflicting and contradictory views. To hold that all religions are equally true is simply not a rational belief.
Biblical View on Other Religions
So what does the Bible have to say about other religions? It teaches that there is a spiritual war going on and the intention of Satan and his host of demonic spirits is to divert us from the truth. The apostle John wrote that "the whole world lies under the sway of the wicked one (1 John 5:19)", and the apostle Paul warned us that people will "follow deceiving spirits and things taught by demons (1 Timothy 4:1)".
From the beginning Satan has been deceiving humanity. In the garden he convinced Eve that "ye shall be as gods". Don't you find it interesting that to be divine "as God" is a common thread among many religions, including Buddhism, Hinduism, Mormonism, and even false Christianity teachings by Kenneth Copeland, Benny Hinn and others1? The Bible also teaches that Satan and his servants will masquerade as ministers of righteousness (2 Corinthians 11:13-14).
Satan's hoisting of false religions has been a very effective lie since it mixes in some truth. A lie mixed in with truth is much like rat poison, which contains 99% good food and 1% poison - its that 1% of poison (or lie) that will kill you!
Biblical View on Salvation
Well, now to the crux of the matter: What does the Bible say about salvation? The Bible plainly and clearly teaches that the only way to heaven is belief in the risen Jesus Christ! The apostle Peter said: "Salvation is found in no one else, for there is no other name under heaven given to men by which we must be saved (Acts 4:12)." Jesus himself said "I am the way and the truth and the life. No one comes to the Father except through me (John 14:6)."
The Bible teaches that sin has separated us from a Holy God, and that the only way to reconcile ourselves with Him is for us to confess our guilt and then to accept His gracious forgiveness through the price paid at the cross by His sinless Son, Jesus Christ.
The Bible makes it very clear that if you do not accept Jesus as your Savior to pay the debt of your sins, then when you die you will not be under God's grace but will instead be judged by God according to the law, which the Bible claims all men past and present have failed, "for all have sinned and fall short of the glory of God (Rom 3:23; also see 1 Kings 8:46, Ecclesiastes 7:20, Isaiah 53:6)".
Since God will not force anyone to love Him, His Holy nature leaves no other choice but to separate the unrepentant from Him forever to suffer eternal punishment in hell.
This may seem harsh and intolerant, but without judgment and punishment God could not remain true to His Holy and Righteous character.
But fortunately the story doesn't stop there, as the Bible tells us of God's wonderful plan for our redemption, that by confessing our sins before God, we will be forgiven and our sin debt will be wiped away through the shedding of his Son's innocent blood at Calvary! It is a gift of such magnitude that it can not be comprehended, for it is neither earned or deserved (Romans 6:23).
It is testimony to the grace of a righteous and holy God who is also incredibly loving and compassionate, who died "while we were still sinners" (Romans 5:8). How many people do you know would lay their life on the line for someone who has persecuted and hated them for years?
Noted author and lecturer Josh McDowell provided a good analogy demonstrating God's just, righteous nature combined with his mercy and grace:
An incident that took place several years ago in California illuminates what Jesus did on the cross in order to solve the problem God had with dealing with the sin of humanity. A young woman was picked up for speeding. She was ticketed and taken before the judge. The judge read off the citation and said "Guilty or not guilty?". The woman replied, "Guilty".
The judge brought down the gavel and fined her $100 or ten days. Then an amazing thing took place. The judge stood up, took off his robe,walked down around in front, took out his billfold, and paid the fine. What's the explanation of this?
The judge was her father.
He loved his daughter, yet he was a just judge. His daughter had broken the law and he couldn't simply say to her "Because I love you so much, I forgive you. You may leave". If he had done that, he wouldn't have been a righteous judge.
He wouldn't have upheld the law. But he loved his daughter so much that he was willing to take off his judicial robe and come down in front and represent her as her father and pay the fine2.
In light of the attributes of God we know to be true in our hearts, such as His holiness, righteousness, compassion, and mercy, Christianity is the only religion that makes sense.
"But he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all (Isaiah 53:5-6).
If what the Bible says is true regarding the spiritual warfare that is going on with Satan and his servants, the fact that there are other religions should certainly be no surprise, nor should it be a surprise that the Bible is attacked by non-believers far more than any other religious book.
Jesus emphatically warned his followers of the many counterfeits and false prophets that would come and try to lead men astray (Matthew 24:11, Mark 13:22, etc.). The other religions of the world have been an effective tool of Satan in his quest to blind us of our need for a Savior.
"The god of this age [Satan] has blinded the minds of unbelievers, so that they cannot see the light of the gospel of the glory of Christ, who is the image of God (2 Cor 4:4)"