Salvation comes from believing that Jesus is the Son of God and part of the Godhead. Jesus came to the earth to reestablish authority over it and to become the atonement for mankind’s sin. Sin is rebellion against God. These are spiritual truths.
Christianity is a representation of the belief in Jesus, but it isn’t the only manifestation. I am ok with that statement. I struggle with the thought that other religions can embrace Jesus and be saved without converting. It isn’t so much that Christianity is the way, but how do you worship Jesus while practicing another religion? Wouldn’t the conflicting views negate each other? How do you serve God while still following other gods? This is where I am tripping up. I don’t think it is possible for a Muslim who has heard the gospel continue with Islam. Mohammed can not be above Jesus. Can you really be agnostic and still follow Jesus?
We see the struggle early Jews had by trying to get Gentiles to conform to their old way of thinking, but those restrictions were removed. There was no unclean food. There were no longer unclean people. They kept trying to get people to convert to their religious views, which was wrong. How do you avoid this with Christianity? Would there be a large group of people who proclaim Christ as Lord but just shunned the title of Christian? Since I cannot visualize it, I struggle to accept it.