It is indeed comforting to believe that all roads lead to salvation, whether it be Islam, Christianity, etc, etc, or just plain human spirituality. I once believed this myself. I’ve received a couple of comments on Can you be both Muslim and Christian? that make me want to repeat this point.
Many churches have risen that welcome all types of spirituality as equal. I’m sure in those churches there are throngs of genuinely wonderful people; some are Christians, some are followers of Christ, some are something else and some make no claims of faith at all. I would hazard a guess that most do not understand that Christ describes himself as the only way to salvation.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
To claim you are a Christian is to claim you are a follower of Christ. So as a Christian, no matter how comforting it is to believe that all good people are on the path to salvation, if we accept Christ’s word as truth, then we know that that good behavior alone won’t get you to heaven. Even the best of us are not good enough on our own.
Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life. (John 8:12)
As I said earlier, I once believed that all roads led to salvation, but a further deeper study of world religions helped me to find my way. Belief in all faiths may somehow bring comfort to some while in this life; belief in Christ alone is the way to bring comfort in the next.