In John 14:6, Jesus says to his disciples, "I am the way and the truth and the life. No one comes to the Father except through me." Some people misinterpret this and say that if you are not a Christian, you won't get into heaven. If non-Christians make it to heaven, it is still through the mercy of Christ with his full knowledge and approval. They will realize that when they get there. Of course, I am not saying that you don't need to become Christians. Christ being the true God, no matter what your belief, you come under his jurisdiction. We need to believe in Christ because he is the way and the truth and the life, and believing in him is the sure way of securing your salvation.